<span style="color: #222222;">The Health Ministry has said surveillance has been enhanced in Uttar Pradesh, Maharashtra and Telangana after traces of Polio Virus Type 2 were found in some batches of oral polio vaccine. The Ministry however asserted that the country remains polio-free.</span><br />'' <br />'' <span style="color: #222222;">It said, a constant vigil is being kept on the shedding of the polio vaccine virus in these areas and it has ordered a probe into the matter. <br />''</span><br />'' <span style="color: #222222;">The ministry's remarks came days after traces of Polio Virus Type 2 were found in some batches of oral polio vaccine manufactured by a Ghaziabad-based pharmaceutical company. It further said no sample has tested positive for wild polio virus in sewage or acute flaccid paralysis cases since 2011. </span><br />