Environmental Correspondent, BBC World Service

Will India be able to stop the India River and two of its tributaries to flow into Pakistan?
This is the question of many minds after India has stopped a large contract governing the sharing of six rivers in Indus pool between the two countries after Tuesday terrifying attack in Indian administered cashmere.
The 1960 Treaty in Indus Waters (IWT) survived in two wars between nuclear rivals and is considered as an example of cross -country water control.
Stopping is a few steps that India has taken against Pakistan, accusing him of supporting cross -border terrorism – the accusation of Islamabad strongly denies. He also pulled away with reciprocal measures against Delhi and said the stopping of the water flow “would be considered an act of war.”
The contract allocated the three eastern rivers – Ravi, Besse and Syu – on India's pool to India, while 80% of the three Western – Indus, Jelum and Chenab – to Pakistan.
Disputes in the past were ignited, with Pakistan objected to some of the projects for hydroelectric and water infrastructure in India, arguing that they would reduce river flows and violate the contract. (More than 80% of Pakistan's agriculture and about a third of its hydropower depends on the water of the Indus pool)

In the meantime, India insists on reviewing and changing the contract, referring to changing needs – from irrigation and drinking water to hydropower – in the light of factors such as climate change.
Over the years, Pakistan and India have been chasing competitive legal paths under the contract, mediated by the World Bank.
But this is the first time the two countries have announced a stop – and more special, it is the country upstream, India, which gives it a geographical advantage.
But what does the suspension really mean? Can India retain or divert the waters of the Indus pool, depriving Pakistan of its rescue line? And can he even do it?
Experts say India is almost impossible to hold tens of billions of cubic meters of water from the western rivers during high -flow periods. It lacks both the massive storage infrastructure and the extensive channels needed to divert such volumes.
“India infrastructure is mostly operated by the river hydroelectric power plants that do not need mass storage,” says Himansho Takkar, a regional water resource expert in South Asia on dams, rivers and humans.
Such hydropower plants use the power of flowing water to rotate turbines and generate electricity without retaining large volumes of water.
Indian experts say that inadequate infrastructure has prevented India from fully using its 20% share of the waters of Jhelum, Cenab and Indus under the contract – a key reason for them to argue for the construction of storage structures, which Pakistan is opposed by the provision of the contract provisions.
Experts say India can now change existing infrastructure or build new ones to restrain or divert more water without informing Pakistan.
“Unlike the past, India will no longer be required to share my project documents with Pakistan,” said G -N -Takkar.

But challenges such as difficult terrain and protests within India themselves for some of its projects meant that the construction of water infrastructure in the Indus pool did not move enough fast enough.
After a belligerent attack on India administered by India in 2016, Ministry of Indian Water Resources Employees had told BBC They would accelerate the construction of several dams and water storage projects in the Indus pool.
Although there is no official information on the condition of such projects, sources say progress is limited.
Some experts say that if India begins to control the flow with its existing and potential infrastructure, Pakistan may feel the impact during the dry season, when the presence of water is already low.
“More careful care is what is happening in the dry season -when the flows through the pool are smaller, storage matters more and the weather becomes more critical,” writes Hassan Fhan, an environmental and ecological research assistant at the University University in the University in the University in the University Dawn newspaper.
“It is there that the absence of contract restrictions can begin to be felt more.”

The contract requires India to share hydrological data with Pakistan – crucial for flooding and irrigation planning, hydropower and drinking water.
Pradeep Kumar Saxena, former IWT commissioner in India for more than six years, told The Press Trust of India News Agency that the country can already stop sharing flood data with Pakistan
The region sees a flood damage during the monsoon season, which begins in June and continues until September. But the Pakistani authorities said India already shared very limited hydrological data.
“India only shared about 40% of the data, even before making the latest message,” said Shiraz Memon, a former Pakistan Commissioner for the Indus Water Treaty, in front of the BBC URDU.
Another problem that arises every time there is a water tension is if the country upstream can “weapons” water against the country down the chain.
This is often called a “water bomb”, where the country upstream can temporarily retain the water and then release it suddenly, without warning, causing great damage down the stream.
Can India do this?
Experts say India would first risk flooding its own territory, as its dams are far from the Pakistani border. However, he can now wash the silt from his tanks without prior warning – potentially caused damage downstream in Pakistan.
Himalayan rivers like Indus carry high levels of silt, which quickly accumulate in dams and barrages. A sudden washing of this silt can cause significant damage down the chain.
There is a bigger picture: India is down China in the Brahmaputra basin, and Indus comes from Tibet.
In 2016, after India warned that “blood and water could not flow together” after a belligerent attack on India -administered Kashmir, China blocks the influx of Yarlung Tsangpo – this became Brahmaputra in Northeastern India – as part of a hydropower project.
After the construction of several hydroelectric plants in Tibet, China has a green illuminated what will be the largest dam in the world of the lower currents of Yarlung Tsangpo.
Beijing claims minimal environmental impact, but India fears it can give China significant control over the river flow.