From the link:
"According to the 2011 census of India, the population of Delhi is 16,753,235."
There is no source for the figure of "Delhi metro area" so not really very scientific is it? 2011 was the last year for which there was census data.
"According to the 2011 census of India, the population of Delhi is 16,753,235."
There is no source for the figure of "Delhi metro area" so not really very scientific is it? 2011 was the last year for which there was census data.