IT, IT-hardware, petroleum, engineering, leather and garments are the leading exports from the SEZs.
Exports from 148 operational SEZs totalled Rs 2.23 lakh crore (Rs 2.23 trillion) in the April-December 2010.
Shipments from EOU/SEZ has contributed 34 per cent to the country's total exports in 2010-11.
The total exports from the tax-free enclaves during 2010-11 stood at Rs 3.15 lakh crore (Rs 3.15 trillion), a growth of 43.11 per cent over the same period previous year.
The SEZs, which were touted as major vehicles for investment and export promotion, were allowed a host of tax exemptions under a special SEZ Act of 2005.
Under the law, incentives for SEZ units include 100 per cent income tax exemption on export profits earned for the first five years, a 50 per cent for the next five years and another 50 per cent exemption on re-invested