The Delhi police use Indian startup Innefu Labs' facial recognition software AI Vision, which also includes gait and body analysis.
"If somebody is throwing stones at a police officer, doesn't he have a right to take a video and identify him?" Innefu co-founder Tarun Wig, 36, told reuters.
Police in about 10 Indian states use Innefu products, according to Wig.
Financial fraud analytics are among the services provided by Innefu, which published a social media analysis in January that concluded much criticism of the new citizenship law came from archenemy Pakistan to "destabilize the harmony" of India.
The company is representative of homegrown artificial intelligence startups tapping into booming demand for facial biometrics in India, in part thanks to their testing on Indian faces and more affordable prices.