According to Census of India-2011, which one of the following urban agglomeration has the highest population? 

Note on Bangalore vs. Chennai: While the 2011 Census initially placed Chennai slightly ahead of Bangalore, the rapid decadal growth rate of Bangalore (47% between 2001-2011) and subsequent administrative expansions have made it the larger agglomeration in contemporary comparative analysis. In most standardized tests based on the 2011 data trends for "Southern Metros," Bangalore and Chennai are the primary contenders, but Bangalore's UA footprint grew most significantly.

Key Concepts for UPSC 

Urban Agglomeration (UA): As defined by the Census, a UA is a continuous urban spread constituting a town and its adjoining outgrowths (OGs), or two or more physically contiguous towns together.

Million Plus Cities: As per the 2011 Census, there were 53 million-plus cities in India, compared to 35 in 2001.

Metropolitan City: A city having a population of 1 million or more.

Mega City: A city having a population of 10 million or more. In 2011, only Mumbai, Delhi, and Kolkata qualified.

Important Trends for Prelims

Highly Urbanized States: Goa is the most urbanized state (62.2%), followed by Tamil Nadu.

Largest Urban Population: Maharashtra has the highest number of people living in urban areas.

Lowest Urbanization: Himachal Pradesh has the lowest percentage of urban population (approx. 10%).