Question

why do we need pressure cooker to cook rice at hill stations

Answer 1

Because, at high altitudes, the atmospheric pressure is low. This causes water to boil at a lower temperature. If we use a pressure cooker, water boils at a higher temperature, before being converted to steam. Thus the food can take more energy from the water.

Answer 2

In hill stations atmospheric pressure is low. So water will boil below 100°c . Therefor cooking is difficult. In pressure cooker boiling point is greater than 100°c because of low pressure .