India is a vast country in geographical terms, with various regions experiences very different climatic conditions. This is also reflected in the distribution of rainfall in India. Some regions experience very high rainfall and others receive very scanty rainfall. The difference between the recorded highest and lowest rainfall in India is approximately 1178 cm. In this article, we will discuss various zones of the country according to the average annual rainfall. This topic is an important part of the Geography Syllabus of the UPSC for Prelims and Mains.
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Rainfall Distribution in India
Precipitation in India is irregular over the course of a year, with a well defined rainy season over most of the country starting in about June and ending in September. According to the Koppen climate classification, it has seven different climatic regions:
- Tropical semi-arid
- Sub-tropical arid desert
- Sub-tropical semi-arid
- Tropical rainforest
- Tropical Savannah
- Sub-tropical humid
The average rainfall in India is 118 cm according to annual data from the Meteorological Department. The following is the distribution of rainfall in India:
- Extreme Precipitation regions: Northeastern regions and the windward side of the Western ghats experience an average of 400cm of annual rainfall. Areas like Assam, Meghalaya, Arunachal Pradesh and hilly tracts of the Western Ghats are host to tropical rainforests. The highest rainfall in India and the world is recorded at Mawsynram village of Meghalaya.
- Heavy Precipitation regions: The regions experiencing 200-300cm rainfall belong to this zone. Most of Eastern India is covered under this zone. These regions are also home to tropical rainforests. States such as West Bengal, Tripura, Nagaland, Manipur, Orissa and Bihar are included in this zone. Most of the areas in the sub-Himalayan belt also fall under this zone.
- Moderate Precipitation regions: Areas which experience 100 to 200 cm of rainfall include parts of West Bengal, Bihar, Orissa, Madhya Pradesh, Andhra Pradesh, and leeward side of the Western Ghats. Wet Deciduous forests comprise the most common natural vegetation of these regions.
- Scanty Precipitation regions: Areas having 50 to 100 cm of rainfall consisting of parts of Maharashtra, Gujarat, Karnataka, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, Punjab, Haryana and Western Uttar Pradesh. Tropical Grasslands, Savannah and Dry Deciduous forests are commonly found in these areas.
- Desert and Semi-desert Regions: These are the areas receive below 50 cm of rainfall. The states of Rajasthan, Gujarat and adjacent areas are classified as desert or semi-desert based on the amount of rainfall they receive. Some parts of Jammu & Kashmir such as the Ladakh plateau are also included in this zone as cold deserts. The vegetation consists of hardy species which can withstand extended droughts. Some areas like parts of Gujarat have Savannah vegetation in the wetter regions. The lowest rainfall in India has been recorded in Ruyli village, Rajasthan.
The rainfall distribution in India is impacted by the Thar desert and the Himalayas. Temperature and pressure changes over the Indian Ocean, the Arabian Sea, the Bay of Bengal and the southern part of the Pacific Ocean also play a significant role in the monsoon rains over the country.
UPSC aspirants should read more on monsoon rains in India for the IAS Geography syllabus. It forms a significant part of the physical, economic and human Geography of the country. Hence, there is almost always a question related to rainfall in the UPSC question papers.
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