CHENNAI: Heavy rains lashed Chennai and its neighbouring districts, marking the first spell of the northeast monsoon, the Regional Meteorological Centre (RMC) said here on Sunday.

Several parts of the city witnessed heavy rains on Saturday night, leaving many localities inundated and causing traffic disruptions.

North Chennai bore the initial brunt, recording between 6 cm and 10 cm of rainfall in less than an hour.

Uthiramerur in Kancheepuram district received the maximum rainfall of 15 cm during the last 24 hours, ending at 5.30 pm on Saturday, followed by a 12 cm downpour at Manalurpet in Kallakurichi during the same period.

The RMC and the India Meteorological Department (IMD) confirmed that the northeast monsoon has entered an active phase.

The heavy showers were driven by an upper-air cyclonic circulation over north Tamil Nadu and coastal Andhra Pradesh, alongside a trough extending from Lakshadweep to the southwest Bay of Bengal.

The IMD has issued a yellow alert for 17 districts, including Chennai, Tiruvallur, Chengalpattu, Kancheepuram, Cuddalore, and Tiruchi, until October 23.

A yellow alert means heavy rainfall between 6 cm and 11 cm.

Meteorologists forecast that widespread rainfall will continue across several districts -- Chennai, Chengalpattu, Tiruvallur, Kancheepuram, Villupuram, Cuddalore, Mayiladuthurai, Nagapattinam, Thanjavur, Tiruvarur, Pudukkottai, Ramanathapuram, Sivaganga, Thoothukudi, Kallakurichi, Ariyalur, Perambalur, Tiruchirappalli, Nilgiris, Coimbatore and Tirunelveli.

Rains are also expected in Puducherry and Karaikal, it said.