New Delhi: The monsoon, vital for farm output in a country with a trillion-dollar economy, is running ahead of schedule and has reached the first landmark of its four-month journey across the subcontinent, a senior weather official said.

The India Meteorological Department (IMD) has forecast that the June-September monsoon will hit the mainland on 30 May, two days before normal, by entering Kerala.

“South-west monsoon has set in over parts of south Bay of Bengal, Andaman and Nicobar Islands and most parts of Andaman Sea," IMD said in a statement on its website.

The monsoon normally reaches its first landmark—the coast of the Andaman and Nicobar islands—on 20 May, and Kerala by 1 June.

“Today, we have declared the onset of south-west monsoon," G.C. Debnath, director of the weather section at the Regional Meteorological Centre in Kolkata, told Reuters on Monday.