Most Indians look forward to the June-September rains for relief from a blazing summer, but the annual season is more than just a cool respite: it's the life-blood of India's rain-dependent economy.
What brings it on?
The monsoon, which spans from June to September, is essentially a reversal of wind patterns: cool oceanic breeze blows over the hot Indian landmass, resulting in rainfall. It starts over Kerala, its first port of call in the Indian mainland, in the first week of June. The rain-bearing system typically covers the whole of India in a month.
During its four-month journey across India, the monsoon hits Kerala in June, its first port of call in the Indian mainland. It then cuts off into two branches - one over the Bay of Bengal and the over the Arabian Sea - before typically covering the whole of India within a month.
Until recently, monsoon was thought to be a distinctly Asian phenomenon. Monsoons do occur in other locations of the world too, such as in Europe, Africa and Chile. Until the 1990s, there was a debate if the June-September rainy season in the US was indeed a monsoon. Meteorologists ultimately classified it as the North American monsoon.
How are rains recorded and the monsoon's progress monitored?
Scientists can now fairly determine the monsoon's course and quality. Monsoon is said to be normal when rainfall is between 96%-104% of 80 centimetres, which is the 50-year average of rains during the season. Rainfall above 110% would mean surplus monsoon.
Why are the monsoons so important for India?
Two-thirds of Indians depend on farm income and over 40% of our cropped area does not have any form of irrigation other than the rains. Millions of farmers wait for the rains to begin summer sowing of major staples, such as rice, sugar, cotton, coarse cereals. Half of India's farm output comes from summer crops dependent on the monsoon. For good farm output, the rains have to be not just robust but also evenly spread across states. The monsoon also replenishes 81 nationally monitored water reservoirs vital for drinking, power and irrigation.
How does the monsoon impact the economy?
When rain-dependent farm output is robust, rural income and therefore spending on almost everything - television sets to gold - goes up. This creates demand for manufactured goods, which helps the general economy. For example, 48% of all motorcycles and 44% of TV sets are sold in rural India. Without this demand, industrial growth would slow down. Normal rains check inflation through plentiful food stocks.
How does deficient rainfall lead to higher prices?
Normal rains act as a strong check on food inflation by increasing food output and availibility. A drought instantly puts pressure on prices. Food inflation, if unchecked, can push up core inflation, such as prices of manufactured goods. The 2009 drought resulted in one of the highest generalised inflation levels seen in almost a decade. Lower food output, a possibility if rains don't pick up in July - the most crucial sowing month -- could knock retail food prices, already high at above 10%.
How critical are this year's rains for the broader economy?
As India, Asia's third largest economy, tries to claw out of a sharp slowdown, a patchy monsoon this year could play spoilsport by threatening to crimp food output, raise prices and pull down farm output necessary for overall growth.
Adequate rains, apart from acting as a strong check on inflation by boosting farm output, are critical for swift recovery, as India's gross domestic product growth is estimated to have slowed down to a decade's low of 5% in 2012-13.
India's agriculture output growth is set to slowdown to 1.8% in 2012-13, down from 3.6% last year, latest national income data showed.
Production of food grains is expected to decline by 2.8% as compared to growth of 5.2 %in the previous agriculture year. The production of cotton and sugarcane is also expected to decline by 4% and 6.5%, respectively, in 2012-13.
Among horticultural crops, production of fruits and vegetables is expected to increase by 3.5% during 2012-13 as against 5.1% in the previous year.
A strong farm sector output is critical to bring down food inflation. High inflation limits scope for the RBI to cut high interest rates, which hamper business activity by making borrowing costlier. A good monsoon raises rural incomes, which helps the economy by fuelling demand for manufactured goods.