Chennai Mayor cautions on possible 50 cm rainfall; civic body speeds up canal work

Chennai Mayor R. Priya has warned that the city might receive more than 50 cm of rainfall in a single spell during the upcoming Northeast monsoon. She said the Greater Chennai Corporation (GCC) has started preparedness work, though it began later than usual.

Speaking to The Hindu on monsoon preparedness, Ms. Priya said that experts have linked the likely heavy rain to El Niño conditions. "Because of El Niño, the rain will be heavy. Right now, even the heat is high for us [in Chennai]. Some experts say that the volume of rain could go even above 50 cm. If it comes in a single spell, it will affect Chennai," she stated.

She drew a comparison with the 2023 Michaung Cyclone, which brought up to 45 cm of rain to the city. "So, they [experts] are saying it could be at that level. Otherwise, the rains might not come at all, and we will be heading into a drought. Either is possible, according to experts at the monsoon preparedness meeting," she added.

On the condition of canals, Ms. Priya emphasised the need for annual desilting. "Just because we have done it this year does not mean it will help us next year. It has to be done every year," she said. The GCC has taken over three canals — Veerangal Odai, Otteri Nullah, and Virugambakkam Canal. She noted that removing water hyacinth is time-consuming and urged the State government to expedite work on waterways with the Water Resources Department.

Admitting a delay in this year's preparedness, Ms. Priya said, "This time, the GCC started preparedness work a little late. We usually begin desilting in June. This year, tenders were floated only in July and the work has now begun in August."

She also pointed out that the Chief Minister's monsoon preparedness meeting held in June was attended only by officials, with no invitation extended to her or the Deputy Mayor.

According to official data shared by the civic body, the GCC has completed improvement works on 21 of the 33 canals taken up across the city, spanning a total length of 15,868 metres. Over 14% of the targeted length remains unfinished. Of the 10,529 metres taken up for improvement, 8,985 metres had been completed as of August 1, 2026.

For the Otteri Nullah, which flows through Royapuram, Thiru.Vi.Ka Nagar, and Anna Nagar zones, works estimated at ₹6,500 lakh were planned. As of August 1, works worth ₹2,637.69 lakh had been completed. The improvement of the existing wall is 75% complete, while construction of new walls is about 25% complete.

For the Virugambakkam Canal in Anna Nagar, Teynampet, Kodambakkam, and Valasaravakkam zones, more than half of the waterway has been desilted this year. Works worth ₹510 lakh had been completed as of August 1. Over 60% of the existing wall has been raised, 40% of the new wall constructed, and 20% of the fencing completed.

The civic body has mapped 294 water stagnation locations and low-lying areas based on last year's data. The Sholinganallur zone recorded the highest number with 76 locations, followed by Royapuram with 31 and Adyar with 26. The Alandur zone recorded zero water stagnation points.

Across these locations, sump and pump arrangements will be made at 10 sites, with 115 motors to be deployed. Mitigation measures will also be implemented at Metro Rail work sites in Anna Nagar, Teynampet, and Adyar zones, and in areas affected by Puzhal surplus discharge in the Manali zone.