Kenyan environmental activist Phyllis Omido has won the prestigious Goldman prize.
She is being recognised for her campaign against a battery smelting plant accused of damaging the health of a community in the city of Mombasa.
As an employee at the plant, she was inspired to act after her baby son was diagnosed with lead poisoning.
The annual Goldman prize highlights the work of community activists and comes with a $175,000 (£117,000) award.
Ms Omido was originally employed by the battery smelting plant in the Mombasa slum settlement of Owino Uhuru to manage its community relations.
The plant was melting down car batteries to extract the lead.
Her young son became very ill after she had been working at the plant for three months.
After tests, doctors discovered that he was suffering from lead poisoning that could have been passed through his mother’s breast milk.
Ms Omido quit her job in 2009 and was encouraged to talk to community members to see if they had suffered any ill effects.
“I wondered about the children who lived in the immediate vicinity of the plant,” she told the BBC’s Newsday radio programme.
She found that people were complaining of health problems, including miscarriages, still-births and high fevers, and chickens were dying after allegedly drinking water that was infected by lead that was coming from the smelter.
Researchers discovered unusually high lead levels in the soil.
Ms Omido then began campaigning for the removal and cleaning-up of the smelting plant but her efforts to talk to the owners were rebuffed.
Working alongside people from Owino Uhuru, they wrote letters to all levels of government and went on marches but the campaign was ignored.
She was told that she was being a nuisance and the community were being “lazy” and that they should be grateful for the employment the plant was bringing.
Finally, after the involvement of the United Nations and international campaign groups, the plant was shut down in 2014.
But Ms Omido’s campaign is not over as she now wants to use the prize money to take the government to court to ensure that the area is cleaned up in line with the constitutional commitment to provide a safe environment for Kenyan citizens.