Rubber- and tea-growing southern state of Kerala received 71 per cent lower rainfall.

Monsoon rains were 20 per cent below average in the week ending on Wednesday, as rainfall was scanty over the central, western and southern parts of the country, the India Meteorological Department (IMD) said, raising concerns over the output of summer-sown crops.

Monsoon rains are crucial for farm output and economic growth, as about 55 per cent of country's arable land is rain-fed, and agriculture forms about 15 per cent of a $2.5 trillion economy that is the third biggest in Asia.

Soybean- and cotton-growing central regions received 68 per cent less rainfall in the week, while the rubber- and tea-growing southern state of Kerala received 71 per cent lower rainfall, data from the weather office showed.

Overall, India has received rains that were 16 per cent less than average since the monsoon season began on June 1.