CHENNAI: Large share of Tamil Nadu’s urban expansion is occurring beyond the reach of formal city governance as a State Planning Commission study has found that nearly 37% of TN’s built-up area lies outside statutory urban local body boundaries of Contiguously Built Urban Agglomerations (CBUAs) and falls within villages and census towns (peri-urban areas).
CBUAs are continuous built-up areas that function as single urban system across multiple local bodies; 316 CBUAs were delineated for the state. Though they share labour markets, infrastructure and economic activity like cities, many parts remain governed as rural areas, creating regulatory gaps and uneven service delivery.
The findings are detailed in a report, prepared by the Tamil Nadu State Land Use Research Board under the State Planning Commission, released on Monday. The report maps peri-urban areas across TN and proposes a Sustainable Urban Management Framework, warning that growth beyond municipal limits is outpacing existing planning laws, institutional arrangements and administrative capacity.
Peri-urban expansion, the study notes, has become the dominant mode of urbanisation in the state. Using two indicators – the scale of built-up area expansion and the share of growth occurring outside statutory town limits – the report identifies 10 priority CBUAs. These agglomerations host TN’s major urban centres, anchor industrial and services-sector activity, and represent its fastest-transforming regions.
Across these priority CBUAs, between 40% and 65% of total built-up growth has occurred in peri-urban belts. The share is particularly high in Hosur (75.5%), Salem (63.7%), Thanjavur (62.2%) and Madurai (57%). Even in larger urban regions such as Coimbatore and Erode, peri-urban areas account for nearly half of the incremental built-up area.
Chennai presents a contrasting pattern. While the metropolitan region recorded the largest absolute increase in built-up area – around 140 sq km over the study period – peri-urban growth accounted for a smaller share, at about 29.5%. The report cautions, however, that the sheer scale of expansion continues to place significant pressure on surrounding areas.
To address these challenges, the report recommends revisiting the Town and Country Planning Act and reforming rural and urban local body laws to explicitly recognise and govern peri-urban areas.
It also calls for the creation of dedicated rural-to-urban transition agencies at the state and district levels, adoption of a regional planning approach, integration of climate risk and blue-green infrastructure into spatial plans, tailored strategies for basic service delivery, and blended financing mechanisms to strengthen local revenues.