Tiger estimation based on camera trap and DNA testing was done after a gap of four years and new areas such as Sunderbans and parts of Maharashtra, Uttarakhand, Uttar Pradesh and Northeast were included for the first time.

Despite that, south India and terrai region in Uttarakhand and Uttar Pradesh accounted for about 40 % of tigers in India. South India now has the highest concentration anywhere in the world of tigers in a region whereas Corbett with around 220 tigers having highest tiger density in a reserve.

There was no change in number of big cat in Central India, touted as tiger capital, with decline in their numbers in Madhya Pradesh, Andhra Pradesh, Orissa and Jharkhand and an increase in Maharashtra, which has surprised wildlife experts.

"We don't agree with the number as of now," said PS Pable, MP's Chief Wildlife Warden. There was also dissent on the estimation from Andhra Pradesh, Uttar Pradesh and Sunderbans, who doubted the methodology of the study. There were 150 tigers in Sunderbans as compared to 70 in present estimation

P R Sinha, director of Wildlife Institute of India, which conducted the estimation, said the numbers have been derived after extensive analysis of data generated through camera traps and local prey population. "The number of tigers have to be in proportion to the prey available," he told HT.

On the scientific note, K Ullas Karanth, director Centre for Wildlife Studies, said the full process of how these tiger numbers are generated for individual tiger populations and landscapes, has not been made public in a scientifically acceptable manner. "Only one scientific paper, which explains only a part of this protocol, has been published in 2011, based on data from the last round of estimation in 2007," he said.

If the tiger estimation of 2006 and 2010 is compared, there is an increase of about 12%, first reported by HT on February 19. "One in every four sq kms of tiger area has been camera trapped," Environment minister Jairam Ramesh said, after releasing the estimation at a global conference of tiger experts.

For Ramesh, the increase was a "mixed bag" as tiger home had fallen by about two million hectares during the two estimation periods and most tiger corridors - linking one reserve with another - were highly fragmented. It has resulted in more tiger deaths because of infighting and tiger-human conflict from Kaziranga in Assam to Corbett in Uttarakhand to Ranthambore in Rajasthan.

Karanth pointed out that most of India's reproducing tiger populations are now concentrated in 10 % of all tiger habitats and are under grave threat. "They need ecologically monitoring annually for protection," he said. Belinda Wright of Wildlife Protection Society of India efforts should be made to improve prey population, which has dwindled in many parks.

For Ramesh poaching was not an issue but outlined threat from development. "The way we plan our national highways and the way we do our coal mining is not going to help future of tigers," Ramesh said. Plan Panel deputy chairperson Montek Singh Ahluwalia countered it by saying that development was not always against conservation of wildlife but emphasized on maintaining a balance between the two.