Even as I observed this congregation of 5000 pilgrims at 4300 metres, ready to pray to the great Vedic deity Shiva at a magnificent mountain lakeside in Gosainkunda, Nepal, I knew that many were in no mood to pray. They were stricken with altitude sickness in its various forms—acute mountain sickness, high altitude pulmonary oedema, and high altitude cerebral oedema.

Acute mountain sickness, which is just like having a hangover, can be relatively benign (with a headache, some nausea, and tiredness), but high altitude pulmonary oedema and high altitude cerebral oedema are undoubtedly life threatening. The initial symptoms of acute mountain sickness are warning signs to be heeded carefully. Alas, many pilgrims climb too high too fast (from Kathmandu at 1300 metres to the lake in two nights) and totally disregard initial symptoms.

Many pilgrims feel that the sickness they experience is caused by the scent of flowers

Just like many impatient tourists that come to trek in …