Rice prices are climbing especially fast, as several rice-producing countries have restricted exports, fearing domestic shortages.

ECONOMIST: Feeding its own people more cheaply

Farmers, especially cotton and rice growers in those upstream states, account for 83% of the basin's consumed water.

ECONOMIST: To turn a drought into wine

The questions around China's rice represents an opportunity for other exporters, especially Vietnam, Pakistan and Thailand, which account for almost all rice imported by China.

WSJ: China Seeks to Calm Anxiety Over Rice

For cadmium to be evident in rice grains as well, the soil in which it was grown must have been especially highly polluted, said Jonathan Wong, a Hong Kong biology professor who has studied mainland soil pollution extensively.

WSJ: Cadmium-Tainted Rice Found in Guangzhou

For cadmium to be evident in rice grains as well, the soil in which it was grown must have been especially highly polluted, said Jonathan Wong, a Hong Kong biology professor who has studied soil pollution extensively on the mainland.

WSJ: Cadmium-Tainted Rice Found in Guangzhou