'Unknown' location advertisement spends were nearly 74% higher than the next biggest spender, Uttar Pradesh.
Sachin P Mampatta and Neha Alawadhi report.
The world's biggest social media platform had an aberration in its spending data on the 2019 general election.
A break-up of the data spends by location showed that the biggest spends originated from a location classified as 'unknown'.
This was followed by other places such as Uttar Pradesh, Maharashtra, Andhra Pradesh, West Bengal, and Delhi.
Further clarification was sought by Business Standard on the data, through an e-mail sent to Facebook. The data was subsequently removed, and an e-mailed statement said there had been a problem in its systems.
'We recently learned of a bug in India's Ad Library Report, which was causing an error. The bug has now been fixed,' said the company statement, suggesting that the location data was erroneously uploaded with an 'unknown location'.
Experts say more transparency is required from social media and other digital giants.
It has been difficult to gauge spends in campaigns, with virtually no figures that can be arrived at on amounts spent in a rally or other political events.
It is even harder in the digital world, pointed out Jagdeep S Chhokar, one of the founders of Association for Democratic Reforms.
"Social media is more elusive. You don't know who is doing what and for whom. Nobody knows except those who actually spent the money. It is possible it is someone who is sitting in Timbuktu," he said.
Social media firms have an incentive against transparency, he said, especially if it is regarding a source of revenue that could dry up if full disclosure is required.
Their regulation is also difficult, considering their global scale.
Regulation of political parties, requiring them to ensure greater transparency on spends may be easier to implement, according to him.
S Yesudas, co-founder and managing director at Y&A Transformation, a company involved in digital consultancy and marketing, said there have been other transparency debates, such as social media giants and making public their correspondence with the Election Commission under the Right to Information (Act.
"Section 11 of the RTI Act makes the public information officer the final authority on such matters even if the third-party has objected to public disclosures," Yesudas said.
"The above, however, are areas where these companies have to work in absolute transparency and in the interest of each specific country they operate in and not for any other interests," he added.
Facebook had begun to make disclosures on its political advertisements after allegations of foreign interference in the 2016 US presidential elections.
Similar allegations had been made about the UK, and its public referendum on whether to leave the EU, which also happened in 2016.
The earlier data, since removed, but of which Business Standard has retained a copy, showed that 'unknown' location advertisement spends were nearly 74% higher than the next biggest spender, Uttar Pradesh, where advertisers spent Rs 2.2 crore, compared to the 'unknown location' spends of Rs 3.9 crore.
This is for the 90-day period ending on May 22.
Total Facebook spends on politics and issues of national importance since February were at Rs 28.2 crore.