Primark (which trades as Penneys in Ireland), one of Europe's biggest fast fashion chains, has pledged to train an additional 125,000 smallholder cotton farmers in more sustainable farming methods in India, Pakistan and Bangladesh by the end of 2023.
The group's sustainable cotton programme trains farmers on using fewer chemical pesticides and fertilisers and less water, thereby preserving the biodiversity and helping to mitigate against climate change.
It also lowers input costs and improves yields and profits for the farmer, the group says.
Primark, owned by London-listed Associated British Foods, said on Friday the commitment would take the total number of farmers in the programme to over 275,000 by the end of next year.
Last September, Primark vowed to cut its environmental impact by using more recyclable materials, making clothing more durable, and improving wages for workers.
It pledged that 100% of the cotton in its clothes would be sourced from its sustainable cotton programme, organic or recycled by 2027.
It also committed to make all its products from recycled fibres or more sustainably sourced materials by 2030.
Currently, almost 40% of Primark clothing is made from recycled fibres or more sustainably sourced materials.
With environmental campaigners singling out the fashion industry for its heavy use of water and chemicals, major brands are coming under pressure to adapt supply chains and address a culture that has led to millions of items ending up in landfill.
Many environmental campaigners are sceptical about green pledges from brands, believing they are driven by a need for good PR and that the industry requires a wider culture change instead.
Primark says its sheer size means it can make a difference.
Last month Primark said it would raise some prices as it battles inflationary pressures.