A spate of deaths at holy sites in the Himalayas has prompted warnings from medical experts that governments are not doing enough to warn pilgrims of the dangers of high altitude.

More than 20 pilgrims from India have died in the past two weeks during the Amarnath Yatra, in Kashmir, one of the holiest pilgrimages a Hindu can make. Devotees trek to above 4,400m to reach a cave featuring a naturally formed ice Shiva Lingam, or phallic symbol. Up to 10 pilgrims from across south Asia also died in the past month from altitude-related illnesses near sacred Mount Kailash, in Tibet.

"Because pilgrims typically ascend very rapidly by helicopter, aircraft or vehicles, they are unable to acclimatise to the altitude," said Buddha Basnyat, the medical commission president of the International Mountaineering and Climbing Federation.

More than 200,000 pilgrims are expected to visit the Amarnath caves this summer. Visitors are required to register beforehand and the official pilgrimage website offers advice on how to reach this remote corner of Kashmir. But advice on altitude sickness is almost non-existent. Pilgrims who feel nauseous are advised only to eat dried fruit or suck lemons.

Basnyat said foreign trekkers were well educated about the risks of altitude, but not pilgrims, for whom the risks were greater. "Unlike trekkers and climbers, there's an element of seeking a cure that attracts a sicker and older population," he said. Pilgrims with conditions such as diabetes and hypertension are more vulnerable to high altitude sickness.

Cultural attitudes can also exacerbate the problem. "Sometimes the … pilgrims feel privileged to die in the precincts of the holy mountain and do not want interventions," Basnyat said.