The Russia-Ukraine war pushes up the price of natural gas, a key ingredient in fertilizer, and has led to severe sanctions against Russia, a major exporter of fertilizer.

Many residents in the city of 26 million have been confined to their homes for up to three weeks as China maintains its "zero-COVID" strategy of handling outbreaks.

The city will require masks in schools, businesses, government buildings and restaurants starting April 18.

Some 29% of baby formula products were out of stock at retailers across the U.S. during the week of March 13, according to the firm Datasembly.