Wal-Mart Stores has deepened its commitment to developing a sustainable supply chain,through measures designed to lessen the environmental impact of global procurement.

Speaking at an event in Beijing, Wal-Mart president and CEO Mike Duke said it will use its sustainability index to make its supply chain more socially and environmentally responsible.

"I'm proud to announce a series of steps and commitments that will make Walmart's supply chain, in the United States, here in China, and around the world, more sustainable," Duke said. "The impact of these commitments will be global and make a difference with products sold around the globe."

Next year, buyers will have specific environmental goals built into their evaluations and the sustainability index will inform the development of private-label goods. 

Wal-Mart said by 2017 some 70% of products purchased for the US market from companies that use the group's sustainability index to evaluate and share the sustainability of products.