NEW DELHI: The Income Tax department is said to have detected over Rs 540 crore black money in the first 15 days of this month. The department started its nationwide operation to check tax evasion on April 1, after the Pradhan Mantri Garib Kalyan Yojana (PMGKY) scheme ended on March 31.Officials said the tax sleuths, in the first fortnight of the new financial year that began on April 1, have conducted multiple search and survey operations on entry operators (agents using banking channels to launder funds), shell firms, government officials, real estate players and other sectors.As per an official data compiled till April 15, the department has carried out "over 250 search and survey operations where the taxman raided at least 300 shell firms and detected more than Rs 540 crore of black money."The action is significant as it comes after the closure of the third black money declaration window of the PMGKY, provided by the government to people holding stash funds to come clean and pay due taxes and penalty, that ended on March 31.The government had brought the first black money declaration window in 2015 for people who held illegal assets abroad followed by the Income Declaration Scheme (IDS) last year where individuals and entities could declare their domestic black funds.The PMGKY was brought by the government in order to check hidden money in the wake of the demonetisation that was announced by Prime Minister Narendra Modi on November 8 last year.A senior official said three major searches were conducted in Noida near here during the said period against an entry operator who was "managing" about 200 shell firms for providing entries of bogus sale and purchase."More than 20 beneficiaries who have received entries of over Rs 1 crore have been identified and the total undisclosed income in this case is about Rs 300 crore," the official said.The official added that a real estate broker in the national capital region, dealing in "unaccounted cash transactions on sale of property", was also covered by the department during the said period and tax sleuths have seized documents leading to tax evasion of more than Rs 50 crore.A senior government official of Uttar Pradesh was also searched during the same period after which, the official said, unaccounted cash payments of Rs 2 crore were detected while four hidden immovable properties in the name of the officer's wife were unearthed.I-T department officials also searched an Ahmedabad-based real estate and infrastructure player where tax evasion to the tune of Rs 120 crore has been detected, the official said, adding the investigations in this case are still on as the case involves multiple layers of bogus entities.As part of a similar search in Pune against a business group, the entity surrendered Rs 19 crore income to the department as the black money was generated "on account of profit not recorded in the books of account."A Hyderabad-based business group engaged in digital printing was also raided by the department which led to the seizure of over Rs 1 crore cash, the official said.The official added that these actions will continue in the coming days as after the closure of the PMGKY window all those cases where black money and tax evasion has been detected will have to be "thoroughly" investigated.