Since June, this is the fourth round of sacking of corrupt tax officials.

The government has compulsorily retired 15 more tax officers in the fourth tranche of its crackdown on errant officials accused of corruption and other malpractices.

The Central Board of Indirect Taxes and Customs (CBIC) -- the agency that oversees GST and import tax collections -- compulsorily retired 15 senior officers under Fundamental Rule 56(J) on corruption and other charges, official sources said.

Since June, this is the fourth round of sacking of corrupt tax officials. In the previous three rounds, 49 high ranking tax officers, including 12 from the Central Board of Direct Taxes (CBDT), were compulsorily retired.

Sources said the action was in line with Prime Minister Narendra Modi's address to the nation from the ramparts of the Red Fort when he had said some black sheep in the tax administration may have misused their powers and harassed taxpayers, either by targeting honest assesses or taking excessive action for minor or procedural violations.

"We have recently taken the bold step of compulsorily retiring a significant number of tax officials, and we will not tolerate this type of behaviour," he had said.

Nearly half of the officials retired were those who were arrested by the CBI for allegedly receiving illegal gratification. One of them was caught accepting a bribe of Rs 15,000. One official is accused of having assets disproportionate to his known source of income.

In June, the government had compulsorily retired 15 commissioner-level officials of CBIC on charges of corruption, collecting and giving bribes, smuggling and even criminal conspiracy. Prior to that, the government had compulsorily retired 12 senior IRS officials from the Income Tax department over charges of corruption, sexual harassment, disproportionate assets under Rule 56(J) of the Central Civil Services (Pension) Rules.

In August, the government compulsorily retired 22 CBIC officials. The Rule 56(J) of Central Civil Services (Pension) Rules, 1972 provides for periodical review of the performance of government servants with a view to ascertain whether they should be retained in service or retired in public interest.

As per these instructions, the cases of government servants covered by FR 56(J), 56(1) or Rule 48(1) (b) of CCS (Pension) Rules, 1972 should be reviewed six months before they attain the age of 50-55 years, in cases covered by FR 56(j) and on completion of 30 years of qualifying service under FR 56(1) or Rule 48 of CCS (Pension) Rules, 1972.