Indian Prime Minister Narendra Modi is making intensive efforts to make the Teesta water-sharing deal agreeable to both Dhaka and West Bengal.

Chief Minister Mamata Banerjee has been included in the prime minister's delegation on his June 6-7 Dhaka trip. The Modi government is trying to explore the possibility of having a "revised" Teesta treaty signed then.

However, Bangladesh wants the original agreement, which could not be inked four years ago due to opposition from Mamata, to remain unchanged.

To help the issue, many proposals are on the table. They include a revised formula under which India and Bangladesh are looking at 46:46 percent sharing of water.

The rest of water will come from the regeneration of the river by the time it enters Bangladesh from India and reaches Dalia barrage in Lalmonirhat.

Out of its share, West Bengal, under the revised formula, has to part with 21 percent of water at Gazoldoba in North Bengal while another 25 percent would be added through regeneration by the time it would reach Dalia barrage, sources in New Delhi said yesterday.

To persuade Mamata, the federal Indian government is offering financial assistance to West Bengal for developing irrigation infrastructure in the state to use Teesta water particularly during the dry season.

Sources pointed out that even now the state can only use 25 percent of Teesta water due to lack of irrigation infrastructure.

It is to be seen how Bangladesh and West Bengal would respond to the formula, sources added.

It was not easy to convince Mamata of the revised formula on Teesta as water requirement for irrigation in vast areas of northern part of West Bengal is politically crucial for her.

The issue is crucial in view of the fact that if her government sacrificed the interests of North Bengal, it might cost her heavily in fresh assembly elections in the state. The polls are due by the first half of next year.

Mamata was unlikely to accept any formula on Teesta unless her government got any tangible assistance from the central Indian government in return.

For this, India's External Affairs Minister Sushma Swaraj, who has good equations with Mamata, has taken a lead role in trying to bring the West Bengal chief minister on board signing the Teesta deal during Modi's visit to Dhaka, said the sources. 

Mamata's close aide and West Bengal Education Minister Partha Chatterjee and Bangladesh High Commissioner to India Syed Muazzem Ali are guarded on the possibility of signing the agreement.

Chatterjee said, "I believe the chief minister will not come in the way of the [Teesta] treaty as long as the interests of West Bengal are not affected by the proposed agreement."

Muazzem Ali told senior journalists of The Indian Express that he was hopeful about a "positive outcome" of the talks in Dhaka on the Teesta during Modi's visit.

He said if the internal discussions between the central government and those in West Bengal and Sikkim states, through which Teesta flows, reach a "conclusive decision," they would be very happy to sign the agreement.

The original Teesta treaty was expected to be signed during former Indian PM Manmohan Singh's Dhaka visit in 2011. But the signing was cancelled at the eleventh hour due to opposition from Mamata.

Pallab Bhattacharya is our New Delhi correspondent