The Income-Tax Department has detected under-reporting of sales worth Rs 408 crore after it conducted a nationwide survey of restaurants on charges of tax evasion, the CBDT said on Monday.

Following the action of visiting their business premises on Sunday, the taxman is now sending emails and messages to as many as 63,000 such outlets "requesting" them to update their income tax returns (ITRs) by March 31, it said.

"A nationwide survey was conducted on 62 restaurants across 46 cities in 22 states. On a preliminary basis, the exercise revealed suppression of sales amounting to around Rs 408 crore," the Central Board of Direct Taxes (CBDT) said in a statement, adding that a probe into these findings is underway.

The statement said the investigation began after the taxman initiated a probe in November 2025 into the food and beverage sector.

"During the exercise, it was found that several restaurants were engaged in deletion of bulk bills and other modifications to suppress the actual sales," it said.

Advanced analytics of transactional data from about 1.77 lakh restaurants was carried out through AI tools, according to the CBDT. This data was compared with the turnover reported by these outlets, leading to the identification of "large-scale" under-reporting of income.

In some cases, the recorded sales were not fully reflected in financial accounts or tax filings, and certain transactions were excluded from reported sales, it said.

Officials had told PTI that the probe began after the department's investigation wing in Hyderabad recently surveyed the premises of a local company that creates restaurant billing software. It was discovered that certain hotels and restaurants were allegedly manipulating the software to under-report their income.