Google's top India counsel, Bijoya Roy, has resigned after 16 months in the role, two sources said, a high-profile exit in a key market where the U.S. tech giant is facing regulatory hurdles and also lacks a government relations head.

India is crucial for Alphabet's Google since most smartphones in the country run on its Android operating system, even as Apple's share is growing steadily.

Google also faces antitrust cases in India, legal challenges over AI training and stricter-than-ever content takedown regulations that started applying to tech companies from February.

Roy quit last month for personal reasons to start her own venture, said one of the sources on Thursday. The two sources declined to be named as the decision is not public.

Google did not respond to a request for comment, while Roy declined to comment.

Last year, Google's head of public policy in India, Sreenivasa Reddy, quit, the second departure for that role in around two years. The company has still not filled the role.

In October, Google said it would invest $15 billion over five years to set up an artificial intelligence data centre in India's southern state of Andhra Pradesh, its biggest ever investment in the world's most populous nation.