Datajam examines Chennai’s rising heat and land use changes

Participants speak at the day-long datajam event on Saturday, 28 September, 2024, organised by OpenCity.in in partnership with C40 Cities, CAG, Poovulagin Nanbargal, and Reach the Unreached
| Photo Credit: Geetha Srimathi

A jamming session in the city, one that doesn’t involve guitars or chords but rather data points on heat stress and urban planning, threw up some insightful results on rising heat in the city.

This summer, most of India faced an unprecedented heatwave, with Chennai recording over 100 days of temperatures above 35℃. Given the scenario, envisioning a better-planned city to mitigate the urban heat island effect is crucial.

At the day-long event on Saturday — organised by OpenCity.in in partnership with C40 Cities, CAG, Poovulagin Nanbargal and Reach the Unreached — a diverse group of urban planners, students, GIS experts, climate researchers, and governance officials came together to analyse public data on temperature, thermal data from satellites, land use, demographics and census data to examine how heat affects vulnerable populations.

32 participants teamed up in groups to examine different areas of the city — Perungudi, Kodungaiyur, Triplicane, Villivakkam, Tondiarpet, Koyambedu — and came out with a common finding: lack of tree cover correlates strongly with increased heat. In Triplicane, the CMDA land use map from 2006 and the proposed map for 2026 revealed a stark decline in tree cover alongside a rise in built-up areas, which coincided with increasing land surface temperatures. 

As Chennai plans for a Waste-to-Energy (WTE) plant at Kodungaiyur, one team examined temperature changes in Pune post-WTE implementation, discovering significant temperature increases in affected wards. They pointed out that establishing a WTE in Kodungaiyur, already burdened by pollution and high carbon emission from the dumpyard, could exacerbate conditions.

For Perungudi, which was a small village just three decades ago and has since transformed into an IT hub, the land surface temperature has shown a marked increase between 2013 and 2023. This rise was attributed to the legacy waste in the dumpyard, which continues to emit methane, contributing to higher heat levels, urbanisation, and the shrinking size of the Pallikaranai marshland.

R. Vaidya from Citizen Matters said that some of the data interpretations will be presented to an official from the Chennai Metropolitan Development Authority.