'The IEAG has recommended a total of six national immunization days, nine sub-national immunisation days and 40 mop-up rounds for the period 2009-10 to 2011-12,' he said.

Pulse Polio Immunisation (PPI) was started in India in 1995-96. This is the largest public health intervention ever taken up anywhere in the world.

As of Aug 14, India has reported 206 case of polio, of which Uttar Pradesh accounts for 159 cases and Bihar for 41 cases. Other states where polio cases have been reported in 2009 are Delhi, Rajasthan and Uttarakhand.

The estimated number of children aged between 0-5 years to be vaccinated on national immunisation days is around 172 million. The sub-national immunisation days in the high risk states will cover about 69 million children up to the age of five. Mop-up immunisation rounds will be undertaken in the districts and in the surrounding areas where polio cases are reported will cover about 7.5 million children.