Indian Monsoon

Before monsoon, land becomes very hot in summer and dry winds may blow. Clouds and rainfall bring relief after monsoon arrives.

Clouds can reduce solar intensity and rainfall gives relief from heat. Therefore the feel of temperature changes during monsoon.

Monsoon affects crop production, reservoirs and rural income. Therefore its economic importance is very wide.

In India monsoon branches, mountains and distance from sea act differently. Therefore regional rainfall differences occur.

A long monsoon break means little or no rainfall for several days or weeks. Soil moisture then declines, and growing kharif crops may not get enough water, causing water stress and possibly lower yield. Option B is incorrect because soil moisture does not remain adequate during a prolonged dry spell. Exam tip: For agriculture, the distribution of monsoon rainfall is as important as its timely onset.

Pre-monsoon rain can moisten soil and give relief from heat. In some regions it helps crop preparation.

The south-west monsoon remains active from June to September and gives India's main rainfall. It is a key feature of India's climate.

The direction of the Aravalli is less effective in lifting the south-west monsoon strongly. Therefore rainfall remains low in western Rajasthan.

The position of the monsoon trough affects rainfall belts. Its shift can cause more rain in some regions and less in others.

In summer the convergence zone shifts northward and links with low pressure. This helps form the monsoon wind system.

Nearness to sea can provide moisture but rainfall also depends on wind direction and mountains. Therefore use combined analysis.

Excessive rainfall increases river flow and surface runoff. This can cause floods in low-lying areas.

A part of monsoon rainfall seeps into the ground and increases groundwater. Therefore rainwater conservation is important.

Monsoon is not limited to agriculture. Water supply, reservoirs and energy systems may also depend on rainfall.

Timing and distribution in monsoon are as important as total amount. Rain at the wrong time can harm agriculture and water management.

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.

A large part of Indian agriculture is affected by monsoon rainfall. Weak monsoon can affect production and prices.

The normal onset of the south-west monsoon starts from the Kerala coast. Then it advances northward and inland through branches.

During retreating monsoon daytime temperature and moisture can create sultriness. Moisture is especially important on the south-eastern coast.

Monsoon takes moisture from the sea and the land-sea heat difference creates pressure system. Therefore the sea has a basic role.