In a major step towards strengthening its biodiversity conservation efforts, Chennai released its City Biodiversity Index (CBI) in the presence of Hon’ble Chief Minister of Tamil Nadu, M. K. Stalin, on 25 August 2025 in Chennai. ICLEI South Asia, in collaboration with the Tamil Nadu Green Climate Company and relevant State and city departments, developed the CBI for Chennai. 

Chennai is the first city in Tamil Nadu to release a City Biodiversity Index, and the 20th city in India to develop one. Building on this effort, in a significant development, Chief Minister Stalin announced that five more cities in Tamil Nadu will work on developing their CBIs. 

The launch was attended by R. S. Rajakannappan, Hon’ble Minister for Forest and Khadi; Tamil Nadu; N. Muruganandham, I.A.S. Chief Secretary to Government; Supriya Sahu I. A. S., Additional Chief Secretary to Government, Environment, Climate Change and Forests Department Secretariat; Srinivas Reddy I. F. S., Principal Chief Conservator of Forests, Head of Forest Force; Mita Bannerjee I. F. S., Principal Chief Conservator of Forests, Member Secretary, Tamil Nadu Biodiversity Board; Emani Kumar, Executive Director, ICLEI South Asia & Deputy Secretary General, ICLEI; and Dr Monalisa Sen, Associate Director, ICLEI South Asia.

The CBI, also known as the “Singapore Index”, comprises a set of quantitative indicators that enable cities to monitor their biodiversity. Developed in 2008 and endorsed at the Convention on Biological Diversity (COP 9), the Index helps cities measure, evaluate, and strengthen biodiversity conservation through 23 globally recognised indicators. 

For Chennai, this Index is a means for balancing rapid urbanisation with the protection of its wetlands, green cover, and native species. The CBI presents data and a roadmap for integrating biodiversity into city planning and enhancing urban green cover, thereby contributing to carbon sequestration, heat mitigation, and improved public health. It also enables data driven decision making for budget allocation, restoration projects, and community participation in conservation. 

In its baseline year of 2024, Chennai scored a total of 38 out of 72 for 18 indicators. While the city showed impressive scores under its “Native Biodiversity in the City”, indicating that its natural habitat supports biodiversity, the Index also highlighted the need for improvement under the “Ecosystem Services provided by Biodiversity in the City”. The section on “Governance and Management of Biodiversity in the City” underscored that biodiversity efforts are being considered by the Greater Chennai Corporation.

This launch follows several initiatives that the Government of Tamil Nadu has taken to conserve and restore its ecosystems, including the Tamil Nadu Wetlands Mission, Green Tamil Nadu Mission, Tamil Nadu Climate Change Mission, and the Tamil Nadu Coastal Restoration Mission, enabling the city to grow sustainably while improving liveability and resilience.

By releasing Chennai’s Index and announcing the development of additional CBIs in the state, the Tamil Nadu Government has reaffirmed its commitment to global and national frameworks, including the Convention on Biological Diversity, the Kunming-Montreal Global Biodiversity Framework, the Sustainable Development Goals and India’s National Biodiversity Strategy and Action Plan. It seeks to inspire other cities to follow Chennai’s example and contribute to the state’s overall biodiversity goals.