The rarefied air with less oxygen makes you feel breathless forcing you to breath faster but that is obstructed by the smell of the shrubs growing around. The smell is actually aromatic and its fragrance enticing under normal conditions but that time when you are breathing and with abundance of it makes you feel sick and you either get used to it sooner or fall sick with fragrance.
There were stories of people feeling sick and some dying due to the smell with symptoms like: giddiness and vomiting when crossing the high mountain passes which is considered, commonly by the locals as ‘ladhu’ its literal translation is ‘mountain poison’. It is believed that people suffer from ladhu due to the smell of the high altitude plants combined with drinking water while trekking the high altitude passes.
I had experienced mountain sickness -ladhu once while going to Lingshi. it was while crossing the highest feature known as nagayla a brownish coloured mountain pass that stood out like a sore thumb and it looked like a sand dune picked up from the Sahara desert and placed it there. The overpowering smell of the scented air that I breath in made me have headache and on further ascend felt little dizzy too. Little did I doubt that I was suffering from HAPE. Luckily, what saved me was that after crossing nagayla it was descending journey losing altitude.
The locals however, advice the one who is suffering from ladhu to cover their nose and breathe as slow and less as possible; a genuine advice if the cause of the symptoms are what they thought to be - the fragrance of the "balu sulu" plant found in abundance oozing very sweet odour in the atmosphere. But how it contradicts the scientific solutions to cure HAPE - the lack of oxygen in the system may get aggravated by covering the nose and trying to breathe less.