A group of activists led by best-selling Indian author Arundhati Roy is on its way back to Delhi at the end of a six-day rally to protest against a controversial dam project.

Arundhati Roy: Leading high-profile protest

The Rally for the Valley, which set off last week, reached the village of Domkhedi on the banks of the River Narmada on Tuesday night.

The rally was a last-ditch effort to stop the dam being filled, but its catchment areas have already started to fill with water.

The group - made up of some 500 activists, artists and celebrities - passed through the village of Jalsindhi, the first area in Madhya Pradesh to be submerged by waters filling the dam, before reaching Domkhedi.

The BBC's George Arney followed the rally

Hundreds and thousand of people gathered on the banks of the Narmada to show their support for the group, chanting slogans saying "nobody will move, the dam will not be constructed".

The state authorities said extra police and security were put in place after Ms Roy said she felt personally threatened by pro-dam activists.

Supporters of the dam argue that the water and power it will provide will be crucial for the entire region, spanning four states in the west of the country (Gujarat, Rajasthan, Madhya Pradesh and Maharashtra).

Arundathi Roy: "It is about much more than just the dam"

But Ms Roy and her group say more than 200 villages will be submerged and nearly a million people displaced by the dam waters.

Controversy has surrounded the dam project since its inception more than ten years ago.