Heavy rain batters Chennai and Tamil Nadu; IMD warns isolated very heavy showers in Ramanathapuram, Pudukottai, Nagapattinam and more. Flood risk & impact.

Widespread rains lashed Chennai and large parts of Tamil Nadu on Oct. 21, 2025, with the India Meteorological Department (IMD) warning of more heavy to very heavy showers in isolated pockets across the state. Chennai recorded 63.5 mm of rain while Ramanathapuram saw 149 mm and Nagapattinam 90 mm in the latest 24-hour bulletin, and TNSMART projected localized totals as high as 170 mm in places such as Thangachimadam. These intense downpours raised flood and waterlogging risk in low-lying city wards and coastal districts.
The rains come as the northeast monsoon intensifies and have already disrupted paddy harvesting in districts such as Tirunelveli and Ambasamudram, where farmers report standing crops and delayed procurement. Local authorities have mobilized drainage and desilting operations; Deputy Chief Minister Udhayanidhi Stalin inspected ₹27-crore waterway renovation works in south Chennai aimed at speeding floodwater flow to the sea, including canal deepening, widening and stormwater drain upgrades.
IMD and state alerts name Ramanathapuram, Pudukottai, Thanjavur, Tiruvarur, Nagapattinam, Mayiladuthurai, Cuddalore and Karaikal as high-risk districts for isolated very heavy rainfall. Residents should follow live IMD updates, avoid standing water, keep emergency numbers handy, and farmers should secure harvested crop and contact local procurement agencies for doorstep collection where available. For SEO, target long-tail queries such as “Chennai heavy rain Oct 21 2025 update,” “which Tamil Nadu districts received 149 mm rain,” and short keywords like “Chennai rain today,” “IMD alert Tamil Nadu” to capture high-intent search traffic.