What is the main reason for increase in humidity during monsoon?

Correct answer: Winds bringing water vapour from the sea

Humidity is the amount of water vapour present in the air. During the monsoon, winds generally blow from the sea toward the land and carry moisture collected through evaporation. As these moisture-laden winds spread over land, the quantity of water vapour in the air increases. This produces higher humidity and supports cloud formation and rainfall when the air rises and cools. Therefore option A is correct. Dry desert winds would usually reduce humidity, while the other choices do not explain the atmospheric process.

The key chain is sea evaporation, moisture-bearing winds, increased water vapour, and then possible clouds and rain. Humidity itself is not liquid water lying on the ground; it is water vapour mixed in the air. Monsoon winds can raise humidity even before heavy rain begins. Rainfall may later remove some moisture, but the arrival of moist winds is the main reason for the seasonal increase. Thus option A accurately identifies the source of the moisture and the reason humidity rises.