New Delhi, July 31 - Commemorating 30 years of freedom from smallpox, the World Health Organization (WHO) Friday said it was the greatest achievement in public health in the 20th century and hailed India's eradication efforts as a 'remarkable feat'.

'Eradication of smallpox is the greatest achievement in public health during the 20th century. This achievement shows that through public health principles, and with unstinted global commitment and solidarity, an available technology could be made equitably beneficial to humankind everywhere in the world,' said Samlee Plianbangchang, WHO regional director for South-East Asia Region.

Plianbangchang was speaking at an event here to mark the occasion that was attended by health professionals, including William Foege, former director of Centers for Disease Control and Prevention (CDC), Atlanta, who played a key role in developing the strategy used for smallpox eradication.

He said there was no effective treatment for this highly contagious disease caused by variola virus, and it killed one-third of those affected and left 65 to 80 percent of the survivors disfigured with deep pitted scars, most prominently on their faces.

'Eradication of smallpox from India was a remarkable feat, with every house in each village visited several times by workers of the smallpox eradication programme,' Plianbangchang said.