The total population divided by available arable land area is referred to as

A form of condensation that reduces visibility and causes breathing problems is

Consider the following pairs;

Tributary Main Piver 
1. Chambal Yamuna 
2. Sone Narmada 
3. Manas Brahmputra

Which one of the pairs given above is/are correctly matched?

The earth is at its maximum distance from the Sun on

Which one of the following is not correctly matched

 Arrange the following in chronological order:

I. Dandi March 
II. Simon Commission 
III. Poona Pact 
IV. Gandhi Irwin Pact