The south-west monsoon has set in ahead of schedule with heavy rains lashing the city on Saturday, the city's weather office said, issuing warning to fishermen against venturing into the sea. Road, rail and air traffic were disrupted badly.

There was water-logging at several low-lying areas on both road and rail routes.

Several vehicles went out of order as water entered their engine making the road travel difficult. Trains are running late, according to railway sources.

Flights were delayed by five minutes to half-an-hour since morning, Mumbai International Airport Ltd (MIAL) spokesperson said.

Two Kingfisher flights -- Kolkata-Mumbai and Delhi-Mumbai -- had to be diverted late last night because of heavy rains, he said.

Met office has also issued warning to fishermen not to venture into the sea as the sea is `rough to very rough' with southwesterly waves. Also there is south westerly to southerly wind from 45 to 55 kmph gusty wind, they said.

 Forecast for next 24 hours till Sunday afternoon is heavy to very heavy rains and thundershower accompanied by gusty winds in parts of city and suburbs, weather officials said.