Gangtok, Oct. 7: A 26-year-old student from IIM Calcutta died yesterday while on his way back from Dzongri, allegedly of altitude sickness.

The student has been identified by Sikkim police as Srinath Damarla, a resident of Hyderabad.

“Damarla died around 9am yesterday at Tshoka. He was a student of IIM Calcutta and was returning to Yuksom after complaining of uneasiness. Prima facie, the reason for his death seems to be altitude sickness. We have registered an unnatural death case,” said West district superintendent of police Rajiv Ranjan. Dzongri, in West district, is 4,030m above the sea-level.

An autopsy was done today at the district hospital in Geyzing, the administrative headquarters of West Sikkim. Two of his family members have arrived, the police said.

Details pieced together from police and tour operators revealed that Damarla was part of a 40-member group on their way from Yuksom to Dzongri. Among the trek group, 26 were foreigners and rest were students from IIM Calcutta.

Yuksom is 138km from Gangtok, and a gateway to Dzongri. The Yuksom-Dzongri trek takes around five days to complete. A road exists only till Yuksom. From there, trekkers have to take the help of guides and porters to reach Dzongri.

On the way to Dzongri on Sunday, Damarla complained of dizziness, headache and body weakness, syndromes associated with altitude sickness.

He tried to come back to Yuksom on October 5 with a guide and some porters. He managed to reach Tshoka (3,000m), a midway point on the Dzongri trek.

“Damarla rested for the night at Tshoka and seemed okay. He had breakfast the next morning and had walked some 15ft down when he collapsed and died,” said a tour operator. The other members of the trekking group are on their way to Yuksom.

Doctors said abrupt climbing to altitudes of more than 15,000ft (or above 4,500m) without proper acclimatisation can lead to complications and even death.

“A person can suffer from high-altitude pulmonary oedema, which is accumulation of fluid in the lungs. This can lead to heart failure or cerebral attack and cause death,” said critical care specialist Subrata Maitra.

“One can also suffer from high blood pressure. Together, these can be termed as high-altitude sickness,” he said. Lukendra Rasaily, the president of Travel Agents’ Association of Sikkim, said TAAS would bear all expenses incurred in bringing down the body. “Whatever help is required, we are providing it. We have asked our members in Yuksom to provide all assistance to the other trekkers,” said Rasaily.

A 69-year-old American trekker had died of altitude sickness on the Dzongri trail in October 2009. The body was brought down with great difficulty to Yuksom, where it was cremated.

The same year but earlier in October, a tourist from Surat had died of altitude sickness in Dzongri.