A petition to challenge messenger service WhatsApp's privacy policy in India is gaining momentum, with the Supreme Court this week issuing notices to WhatsApp, its owner Facebook, and the telecom regulator TRAI to respond to the court within two weeks.

The petitioners are incensed over WhatsApp's changes to its privacy policy in September last year, which saw it begin sharing users information with Facebook, including their phone numbers. Those who didn't agree with the new policy were given the option to "opt out" by deleting the app. This announcement came two years after WhatsApp was acquired by Facebook.

Last year, the Delhi High Court allowed WhatsApp to continue with its new policy, but ordered the messenger service to delete the data of users who deleted WhatsApp before its new privacy policy began. It also ordered TRIA to begin looking into whether messenger services could be brought under existing telco regulatory frameworks.

Last week, the Supreme Court began hearing the appeal to last year's High Court decision, with lawyers for the petitioners arguing that 155 million users in India are affected by the new privacy policy, and that it is in violation of constitutional rights, including freedom of speech and right to personal liberty. Interestingly India's privacy laws don't seem to have been robust enough to support the claim on its own.

We'll keep you updated as the case develops.