"Income Tax department had carried out the survey in April this year on certain corporates on TDS violation wherein names of NIIT, HCL and IOC have figured," sources in the I-T department said.

Employees in these companies were given certain allowances under heads such as uniform allowance, professional upgradation allowance among others, which have been found to be claimed as exempted from income tax, sources said. These were claimed as miscellaneous rebates by the companies.

"Investigations in the TDS violations by the companies which figured in the survey are still on," sources said, adding that details like the amount of evasion could not be disclosed as it might affect the process of investigation.

The Income Taxdepartment has launched a major drive this year for tds collections and thus evasions under TDS are taken very seriously.

The Income Tax department is planning to launch a massive drive against corporate houses and multinationals defaulting in TDS.

As many as 73 foreign companies and nine domestic companies had defaulted in tax deduction at source payment in 1998-99.

"The department had conducted a similar survey on multinational companies operating in India last year, which revealed TDS defaults by many MNCs," sources said, adding that these companies had not been deducting tax at source on the salaries of their expatriate employees for the period of employment in India paid abroad.

After the survey the TDS collections witnessed an upsurge. While the total tax collections in Delhi for the year 1998-99 was Rs 8400 crore, TDS collections stood at Rs 600 crore.