In a 194-page complaint, NDTV alleges that Nielsen, Kantar and TAM “are liable for indulging in corrupt practices by manipulating viewership data in favour of channels that are willing to covertly provide monetary inducements/payments/bribes to TAM officials”.

NDTV claims that “wilful negligence and manipulation” of TAM’s viewership data has been going on “since at least 2004” and that the channel’s own ratings and ad revenue has suffered because it has “refused to indulge in any corrupt practices”. NDTV says it has lost at least $810m over the years because of the alleged false ratings data. It is seeking that and more in damages.

In January this year, NDTV says, it wrote to Nielsen CEO David Calhoun to complain about the losses the business was suffering as a result of the alleged manipulation of ratings information. Later that month NDTV officials met with senior representatives of Nielsen and IMRB (a Kantar-owned company). Further meetings were also held at which NDTV claims Nielsen and Kantar executives made repeated promises to address NDTV’s concerns. “Those promises have been broken,” the company alleges.

NDTV said it asked Nielsen and Kantar to stop publishing TV ratings data in India until there was an increase in sample size from 8,000 to 30,000 measured households and an increase in security measures. NDTV claims that “no such remedial measures have been taken”.

A Kantar spokesman declined to comment when approached by Research, as did a Nielsen executive when approached by The Hollywood Reporter, which first broke the story.