Two of India's most famous rivers have been given the status of living entities to save them from further harm caused by widespread pollution.

The High Court in the northern state of Uttarakhand ruled that the Ganges and Yamuna rivers - considered sacred by nearly a billion Hindus in the country - be accorded the status of living human entities, meaning that if anyone harms or pollutes them, the law would view it the same as harming a person.

The judges cited the example of New Zealand's Whanganui River, revered by the indigenous Maori people. The Whanganui was declared a living entity with full legal rights by New Zealand's government last week.

The Uttarakhand court, in the Himalayan hill resort town of Nainital, appointed three officials to act as legal custodians responsible for conserving and protecting the two rivers and their tributaries.

Judges Rajeev Sharma and Alok Singh declared the Ganges and the Yamuna and their tributaries "legal and living entities having the status of a legal person with all corresponding rights, duties and liabilities".

The case came to court after officials complained that the governments of Uttarakhand and the neighbouring state of Uttar Pradesh were not co-operating with federal government efforts to set up a panel to protect the Ganges.

The court ordered that the Ganga Management Board be set up and begin working within three months.

Environmental activists say many rivers across India have become dirtier as the country's economy develops, with city sewage, farming pesticides and industrial effluents freely flowing into waterways despite laws against polluting.

Vimlendu Jha, an environmental activist fighting for more than a decade to clean up the Yamuna, said the court ruling would not be enough to stop the degradation of the rivers.

"Merely announcing that it is a living entity will not save the river," Mr Jha said. "The state government, officials and citizens need to act to clean up the river and stop further pollution.

"The two rivers have to be fixed, or we will face a huge ecological and health crisis."

Officials say the Yamuna, one of the main tributaries of the Ganges, is tainted with sewage and industrial pollution. In some places, it has stagnated to the point that it no longer supports fish or other aquatic life.

Water from the Yamuna is chemically treated before being supplied to Delhi's nearly 19 million residents as drinking water.