High (altitude) tea

Yes!

distaff

I remember reading this thread years ago, but didn't get around to posting the answer....
Pressure cookers.
It might seem a little extreme, but this is the answer to making tea at high altitude. Indeed, for making any staple indian food; rice, veg and dal will have problems cooking properly at the lower temperature of boiling water at altitude.
The pressure in a pressure cooker means the water will boil at higher than normal temperatures.

In the household goods stores at Leh (Ladakh), you will find a range of sizes of pressure cooker, all the way down to tiny little 500ml chai-capacity. I remember asking about them, and was told that sheperds bought them to make chai while tending their flocks in the high summer pastures.
Have seen them used by the dhaba wallahs at Pang on the Leh-Manali route.

Pfff. Man (woman), your tea wil be boiled, and hence safe.

and ever so slightly stewed