Question

boiling point of water on hill station like Shimla is lower than in delhi why

Answer 1

Boiling point of a liquid is defined as the temperature at which the vapour pressure of the liquid equals the pressure of the gas that lies above the liquid, or the atmospheric pressure. Now, on hill stations like Shimla, or any other high altitude region for example, the atmospheric level is lower than the other regions.

This means that the temperature at which the vapour pressure of a liquid (water) will equal the atmospheric pressure would be lower too. This therefore implies, that the boiling point of the liquid would be reduced at higher altitude.