By Subir Bhaumik BBC News, Kaziranga national park

Forestry officials in the north-east Indian state of Assam have demanded the creation of a no-pesticide zone around the famous Kaziranga game sanctuary.

The call follows the deaths of two pregnant elephants and other animals in tea estates around Kaziranga.

The national park is renowned for its varied wildlife, especially the tiger and the one-horned Indian rhino.

Officials say that mammals and birds were killed after eating grass that was contaminated by pesticides.

The two elephants ventured out of the park in search of food and ate grass which had been sprayed to kill red ants, officials say.

"The death of these elephants has brought the pesticide issue to the limelight, because the chemicals sprayed in tea estates are playing havoc with wildlife in our forests which are surrounded by hundreds of tea estates," said Anurag Singh, a senior forestry official in northern Assam where Kaziranga is located.

The area has the highest concentration of tea estates in India.

"The managements of these estates must turn to organic farming and stop spraying chemicals," Mr Singh said.
'Endangering our wildlife'

He added that hundreds of birds have died in the same area as has livestock which has eaten pesticide-laced grass in recent weeks.

"The cows died in their dozens and the vultures who fed on them also died in large numbers. So you can imagine the effect on human health when consumers drink these teas," Mr Singh said.

He said the forestry department was contemplating the prosecution of some tea estates if animals - especially those that are endangered - are killed by the pesticides.

Local community groups also support a pesticide ban.

"The tea estates should go organic and stop spraying random pesticides. They are not only endangering our wildlife and aquatic life but also our people," said Moni Manik Gogoi, who heads a "people's committee" near Kaziranga.

Some tea estate owners have also supported the call, especially those who run estates which are fully organic.

"Unless we all go organic, our teas will be under a scanner and we will lose lucrative markets where consumers are very health conscious," said Binod Saharia, owner of the Gossainbarie tea estate near Kaziranga.

But some planters are wary of losing out if they make the transition.

"The tea industry is so used to chemicals because they represent the easy option when combating plant diseases like halepeltis," said HS Siddhu, a veteran tea planter in Northern Assam.

He said the planters should be persuaded rather than being forced to convert to organic farming.