Tightening the noose, the government has seized more aircraft of leading corporates like GMR, Oberois, India Bulls and has brought under scanner over 250 such planes acquired since 2007 to detect duty evasion.

Any body found guilty of acquiring aircraft with duty exemption under Non-scheduled Operator Permit Scheme could be levied penalty up to five times the duty evasion, a finance ministry official said.

Sources in the Customs department said that as many as six aircraft were seized this month but released after the owners provided a bank guarantee and bonds in relation to the cost of aircraft.

The issue had first come up with seizure of two aircraft of Reliance Industries, but now planes belonging to corporate bigwigs like Tata, DLF, Escorts, Kingfisher, Punj Lloyd have come under government scrutiny.

Though there is no official estimate of the duty evasion, sources in the know indicated that government could collect over Rs 10,000 crore by way of tax and penalty.