Duress”. Duress is where a man is compelled to do an act by injury, beating or unlawful imprisonment (sometimes called duress in strict sense) or by the threat of being killed, suffering some grievous bodily harm, or being unlawfully imprisoned (sometimes called menace, or duress per mines). Duress also includes threatening, beating or imprisonment of the wife, parent or child of a person.Duress would also include“ psychic torture, atmospheric pressure, environmental coercion, tiring interrogative prolixity, over bearing and intimidating methods, and the like”. Any mode of pressure, “subtle or crude, mental or physical, direct or indirect, but sufficiently substantial”, applied by the police to obtain information from an accused strongly suggestive of guilt becomes compulsion
The protection under Art 20(3) is available to a person who is compelled to give evidence against himself. There has to be the element of “compulsion” to give evidence on the part of the accused.

Therefore Narco Analysis very well comes under the umbrella of forced or compelled testimony. The consent of the accused is ignored. He is subjected to a dose of Sodium pentothal after which in an unconscious state of mind he answers questions put forth to him.
 
Narco Analysis Test refers to the practice of administering barbiturates or certain other chemical substances most often sodium pentothal, to lower the subjects inhibitions in the hope that the subject will more freely share the information and feelings. In such sleep-like state, efforts are made to obtain “probative truth” about the crime.
It becomes difficult for the person to lie and his answers would be restricted to facts he is aware of.^[3]
 
Therefore by subjecting a person to Narco analysis is akin to compelling him to be a witness and compelling him to give evidence against himself. The protection against this is guaranteed under Part III of the Constitution.
And hence if such test is conducted against their will, it will be infractuous in evidence even though this test is conducted by an expert.
 
Further the legal maxim Nemo tenetur seipsum accusares which means “No man is bound to accuse himself”.
The right to remain silent, as it is officially called, is a legal right of any person subjected to police interrogation or summoned to go to trial in a court of law. This right is recognized, explicitly or by convention, in many of the world's legal systems.
The right usually includes the provision that adverse comments or inferences cannot be made by the judge or jury regarding the refusal by a defendant to answer questions before or during a trial, hearing or any other legal proceeding. This right constitutes only a small part of the defendant's rights as a whole.
The ban on Self Accusation and the Right to Silence, while investigation or trial is underway, goes beyond that case and protects the accused in regard to other offence pending or imminent.
 
Therefore inadvertently denied of his Right to Silence. He has no other choice but to answer the question in the hypnotic trance. Moreover his right to call a lawyer is also denied to him.
 
The Supreme Court has ruled that the confession has to be voluntary; a confession made under a threat, inducement or compulsion is inadmissible. Article 20(3) would not apply if confession is made otherwise than under threat, promise or inducement. A retracted confession has little probative value but is not inadmissible under article 20(3).^[4]
 
In the unconscious state of mind reveal statements which might be used against him. The essence that such statement is given voluntarily, does not arise when the petitioner is compelled to go under Narco Analysis Test.
 
Morover, the Narco analysis Test is widely popular for in lack of conclusiveness and inability to ascertain the truth in the cases. This has been clearly elucidated in the case of State v. Pitts the use of Sodium Amytal in Narco Analysis was prohibited because the results of the interview were not considered scientifically reliable. The court opined that subjects are susceptible to filling in gaps in stories with fabricated detail (hyper amnesia), or believing in false events (memory hardening), and hypnotic recall, where thoughts of non-existent events become embedded in the memory. Therefore the test results should not be regarded as conclusive evidence there should be a need of corroborating statements made during Narco Analysis with other evidences that have been procured.
Article 21, which guarantees-
 
“No person shall be deprived of his life and personal liberty except according to procedure established by law.”
The expression “life” in article 21 has been interpreted by the Supreme Court rather liberally and broadly. Over time, the Court has been giving an expansive interpretation to “life”. The Court has often quoted the following observation of Field, J.:
“By the term Life, as here used something more is meant than mere animal existence. The inhibition against its deprivation extends to all those limbs and faculties by which life is enjoyed. The provision equally prohibits the mutilation of the body by the amputation of an arm or leg.”^[5]
Similarly In State of Punjab v. Mahinder Singh Chawla[35] the Apex Court has held that the right to life includes right to health. Subjecting a person to an unsafe scientific test as part of investigation will amount to denial of right to health^[6]
Narco analysis is not a safe method of interrogation since the use of such drugs could lead the subject to various health
Bhagwati, J., has observed that the right to life includes the right to live with human dignity and all that goes along with it, namely, the bare necessaries of life such as adequate nutrition, clothing and shelter over the head and facilities for reading, writing and expressing oneself etc… ^[7]
The Supreme Court has taken a very positive stand against police atrocities, intimidation, harassment and the use of third degree methods to extort confession. The Court has characterized all this as being against Human Dignity.
Subjecting a person  to Narco Analysis he will be also subject to the embarrassment of being in a sub-conscious state answering questions under the influence of a drowsing barbiturate. Is not this a clear violation of his Right to Live in Human Dignity?
 
While police is entitled to arrest a criminal and interrogate him during the investigation of an offence, the law does not permit the use of third degree methods or torture of an accused in custody during interrogation and investigation to solve a crime.
The object of Article 21 is to prevent encroachment upon personal liberty by the executive, save in accordance with law.^[8]
The right to privacy is not expressly mentioned in the Constitution, but falls within the ambit of the ‘personal liberty’ guaranteed under Article 21 of the Constitution. 
Narco Analysis arguably falls within the scope of Article 21 by virtue of the invasion of the body and mind, which constitutes an invasion of privacy. There is a risk that the unconscious mind may reveal personal information that is irrelevant to the investigation. It is therefore imperative to establish standards of confidentiality and other safeguards, as privacy can be violated only by “procedure established by law”. No such safeguards exist in India and therefore Narco Analysis particularly if performed without consent amounts to a violation of privacy
 
At a criminal trial the accused is entitled to a presumption of innocence and the prosecution is bound to prove all the ingredients of the charge beyond reasonable doubt.^[9]
the burden rests on the state to establish the constitutional validity of the impugned law
Section 45 of the Indian Evidence Act, 1872 allows experts’ opinions in certain cases.
It says: “When the court has to form an opinion upon a point of foreign law, or of science, or art, or as to identity of handwriting or finger impression, the opinions upon that point or persons especially skilled in such foreign law, or of science, or art, or as to identity of handwriting or finger impressions are relevant.”
However this section is silent on other aspects of forensic evidence that can be admissible in court in criminal proceedings.
It would be wrong to include Narco Analysis among these when it has not been specifically mentioned therein. Therefore it comes out of the term of “procedure established by law”.
The use of Sodium Amytal in Narco Analysis was prohibited because the results of the interview were not considered scientifically reliable. The court opined that subjects are susceptible to filling in gaps in stories with fabricated detail (hyper amnesia), or believing in false events (memory hardening), and hypnotic recall, where thoughts of non-existent events become embedded in the memory. Therefore the test results should not be regarded as conclusive evidence there should be a need of corroborating statements made during Narco Analysis with other evidences that have been procured.^[10]
Further more wrong dose can send the subject into coma or even result in death .the rate of administration is controlled to drive the accused slowly into a hypnotic trance. The effect of the bio-molecules on the bio-activity of an individual is evident as the drug depresses the central nervous system , lowers blood pressure and slows the heart rate, putting the subject into a hypnotic trance resulting in a lack of inhibition the subject is then interrogated by the investigating agencies in the presence of the doctors.
The subject which is put in a state of hypnotism is not in a position to speak up on his own but can answer specific but simple questions after giving some suggestions. The subject is not in a position to speak up on his own but can answer specific but simple questions
It is explicitly proclaimed in Article Ten of the Universal Declaration of Human Rights, the Sixth Amendment of the US Constitution, and Article Six of the European Convention of Human Rights.
Moreover, article 14.3(g) of the U.N. Covenant on Civil and Political Rights, 1966, provides:
“In the determination of any criminal charge against him, everyone shall be entitled to the following minimum guarantees, in full equality:
(g.) “Not to be compelled to testify against himself or confess guilt.”
 
Article 6(1) of the European Convention for the Protection of Human Rights and Fundamental Freedoms, 1950, provides:
 
“In the determination of his civil rights and obligations, or of any criminal charges against him everyone is entitled to a fair and public hearing within a reasonable time by an independent and impartial tribunal established by law.”
 
It was further explained that although not specifically mentioned in Article 6 of the Convention, there can be doubt that the right  to remain silent under the police questioning and the privilege against self-incrimination are generally recognized international standards which lie at the heart of the notion of a fair procedure under Article 6. By providing the accused with protection against improper compulsion by the authorities these immunities contribute to avoid miscarriages of justice and to securing the aim of Article 6.
 
It is a general immunity, possessed by all, from being compelled on pain of punishment to answer questions and the answer, may incriminate them.
 
The Preamble of the International Covenant on Civil and Political Rights (ICCPR) states the following:
The States party to the present Covenant, in accordance with the principles proclaimed in the Charter of the United Nations, recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world, Recognizing that these rights derive from the inherent dignity of the human person, Recognizing that, in accordance with the Universal Declaration of Human Rights, the ideal of free human beings enjoying civil and political freedom and freedom from fear and want can only be achieved if conditions are created whereby everyone may enjoy his civil and political rights, as well as his economic, social and cultural rights, Considering the obligation of States under the Charter of the United Nations to promote universal respect for, and observance of, human rights and freedoms, Realizing that the individual, having duties to other individuals and to the community to which he belongs, is under a responsibility to strive for the promotion and observance of the rights recognized in the present Covenant.
 
Part 3, Article 7 of the International Covenant on Civil and Political Rights (ICCPR) states the following, “No one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment. In particular, no one shall be subjected without his free consent to medical or scientific experimentation”
The use of the truth serum test in considered as a torture in the international regime. The UN definition of torture clearly implies that the tests performed for obtaining information from suspects, amounts to severe mental suffering or coercion, hence, leading to torture. It has been evidently stated by the UN Committee against Torture that an authorized mode of application of ‘moderate physical pressure’ breaches the convention against torture.
Amnesty International declares the administration of Sodium Pentathol or any other truth serum for procuring information as amounting to torture on the grounds that it is cruel, inhuman and a degraded treatment. Hence, this process should be prohibited. Such a process also outlaws the international standards of interrogation.
The use of evidence obtained under duress has been prohibited by The Human Rights Committee by stating-“the law must prohibit the use of admissibility in judicial proceedings of statements or confessions obtained through torture or other prohibited treatment.’’ The Committee has further stated that, “the law should require that evidence provided by … any… form of compulsion is wholly unacceptable.” Use of drugs has been documented as a form of torture in a number of countries, including Chile and the former Soviet Union. It has also been noted that under US case laws confessions made under the influence of truth serums are also not “voluntary” and are consequently inadmissible as evidence.
India has still not ratified The UN Convention against Torture, though it has signed the same. 
 

[1] The State of Bombay V. Kathi Kalu Oghad and Ors. AIR1961SC1808
[2] Nandani Satpathay v. P.L Dani, AIR 1978 SC 1025 : (1978) 2 SCC 424
[3] Kumari, S. Kusuma, Narco Analysis Right to Self Incrimination v. Public Interest, (2007)                                                                                  Cri LJ  (June) pp. 137- 141, All India Reporter, Nagpur, 2007. p.138
[4] Kalawati v. State Of Himachal Pradesh ,AIR 1953 SC 131:1953 SCR 564.
[5] Munn v Illinois 94 US 113 (1877)
[6] State of Punjab v. Mahinder Singh Chawla  AIR 1997 SC 1225.
[7] Francis Coralie v Delhi AIR 1981 SC 746
[8] G. Gurunadha Reddy v A.P. Road Transport Corporation AIR 1999 A.P. 179
[9] Woolmington v D.P.P (1935) AC 462
[10] State v. Pitt