Additional district and sessions judge of Sealdah court, Anirban Das, awarded life imprisonment till death to convict Sanjay Roy for the crime. The prosecution had prayed for the death penalty for the convict.
The victim's parents, a section of doctors and civil society organisations said they are unhappy with the order and will move the higher court.
Das said that the measure of a civilised society lies not in its ability to exact revenge, but in its capacity to reform, rehabilitate and ultimately to heal.
"In the realm of modern justice, we must rise above the primitive instinct of 'an eye for an eye' or 'a tooth for a tooth' or 'nail for a nail' or 'a life for a life'," the court observed.
"Our duty is not to match brutality with brutality, but to elevate humanity through wisdom, compassion and a deeper understanding of justice," the trial court judge said in the 172-page judgement.
He said that this case does not meet the stringent criteria for being classified as "rarest of the rare".
The judge said that the Supreme Court has consistently emphasised that the death penalty should be used only in exceptional circumstances where the collective conscience of the community is so shocked that it expects the holders of judicial power to inflict the death penalty.
Judge Das said that given these considerations, it would be inappropriate to accede to the prosecution's request for the death penalty.
"While acknowledging the immense grief and suffering of the victim's parents, for which no sentence can provide complete solace, the court's duty is to pass a sentence that is proportionate, just and in accordance with established legal principles," the court observed.
While ordering rigorous imprisonment for life and a fine of Rs 50,000 each on two counts of rape and murder and rigorous imprisonment for the remainder of the convict's natural life for causing injury during the act of committing rape on the victim that led to her death, the court directed that all the sentences will run concurrently.
"In the instant case, it was established that at the time of commission of the offence of rape, the accused committed throttling associated with smothering, which was the proximate cause of death of the victim.
"Accordingly, without any hesitation, I hold that the charge under Section 66 (punishment for causing death or resulting in persistent vegetative state of victim) of Bharatiya Nyaya Sanhita (BNS) was also established against this accused," the court said in its order.
Observing that the convergence of forensic findings - the physical evidence of sexual assault and the DNA matches from various samples - constructs a compelling scientific narrative, the court said that it not only confirms the presence of Sanjay Roy at the place of occurrence but also directly links him to the violent acts perpetrated against the victim.
The court said that the forensic evidence forms a cornerstone of the prosecution's case, offering objective, scientific corroboration of the charges and leaving little room for alternative explanations.
"The nature of this crime is particularly heinous, characterised by its brutality and the vulnerability of the victim.
"The act of manual strangulation coupled with smothering indicates a prolonged and deliberate infliction of suffering," the court said, observing, "the additional element of sexual assault compounds the gravity, reflecting a complete disregard for human dignity and life.