Launched in 2020, the annual prize champions what it terms "groundbreaking leadership" and cutting-edge solutions.

The past five host cities were Rio de Janeiro in 2025, Cape Town in 2024, Singapore in 2023, Boston in 2022 and London in 2021.

As with previous competitions, this year's winners will receive one million pounds ($1.3 million) each "to accelerate the impact of their innovative solutions", organisers said.

This year's prize will highlight environmental solutions under five categories -- Protect and Restore Nature, Revive our Oceans, Build a Waste-Free World, Fix our Climate and Clean our Air.

The choice of Mumbai focuses attention on India's struggle to combat air pollution.

A 2024 study in The Lancet Planetary Health estimated that 3.8 million deaths in India between 2009 and 2019 were linked to air pollution.

India is home to more previous Earthshot prize winners and finalists than any other country.

Prince William described it is as one of the world's "most important forces" for climate and nature.

"What succeeds in India at scale has the power to inspire progress everywhere," he said.

"With the largest population of young people in the world, there is a real sense of momentum -- to not only imagine a better future, but to inspire change and make it a reality.

"Together we can rise to meet our greatest challenge, to repair and restore our planet by 2030."

The heir to the British throne has attended every Earthshot prize ceremony so far, all of them in November