Bollywood megastar and UNICEF goodwill ambassador Amitabh Bachchan is happy with the drop in numbers of polio-affected children in India and hopes that the country will get totally free from the disease.

"For one whole year for the first time since I took over the brand Ambassador of Polio UNICEF campaign, we have zero cases in India. Feel proud and delighted that finally our efforts have been successful. Started in 2002, with over 1000 cases and today just one in West Bengal, " Amitabh posted on micro-blogging site Twitter.

"This year's Polio Campaign... no case reported from Uttar Pradesh and Bihar, which are most vulnerable states. Only one case in West Bengal!" he added.

The actor attended an event in Mumbai Thursday where he launched a new UNICEF campaign for polio, and was feted by the government and UN officials for his work towards polio eradication.

"And UN officials tell me that hopefully by early next year we shall be able to announce that India is finally free of polio... I am so delighted that the polio eradication campaign and my incessant plea of 'do boond zindagi ke', has proved so successful!!

"But let's not sit back, let's keep at it to completely free our country of this dreaded disease... each Indian owes this to the nation, " added the 69-year-old, who recently welcomed a grandchild, a baby girl -- the first to be born to his son, Abhishek, and daughter-in-law, Aishwarya.

The veteran star also thanked other celebrities who were involved in the campaign, and gave a word of advice to all parents.

"May I also add here that polio is incurable, but it can be prevented provided the vaccine is taken in time... And yes, on some of the campaign videos I did invite Sachin (Tendulkar), Aishwarya, SRK (Shah Rukh Khan), and Jaya (Bachchan) to promote the cause... so thank you to all!!" he wrote.