Word has it that China's weather forecasters expect rain in the next few days, but they are too skittish to make an official prediction. That is understandable, given the stakes. Gripped by its worst drought for 60 years, the world's biggest wheat producer is desperate for a downpour to avoid a crop failure that would have an impact on food prices around the world.

The challenge is evident from the burst of recent reports in the Chinese media about food, water and the environment.

Grain hoarding is already a problem, according to TV report about farmers who are reluctant to sell their stocks because they expect the price to increase in the near future. China News quoted the manager of Yucheng Xinfeng flour mill in Henan complaining about the difficulty of securing supplies since the start of the Chinese new year.

"In the two months before the Spring festival, we were getting several hundred tonnes a day, but now we get only 30-40 tonnes. There are a lot fewer sellers because some people are still on holiday and because of the drought."

There is still time to save the crop. As I noted in an earlier report from Shandong – one of the worst-affected provinces – the government is digging new wells as part of a billion-dollar emergency package. It has also pledged to use its large grain supplies – helped by a record harvest last year – to ease inflation pressures.

But the influence of the authorities is limited. The political turmoil in the Middle East is driving up oil prices , which have a close correlation to grain costs due to the overlap of biofuels and the dependence of modern agriculture on fossil fuels.

Even without the complication of climate change, water scarcity in China is a long-term problem that has been exacerbated by the growing demands of agriculture, industry and urban centres. The impact is not only felt in the dry north, but in the manufacturing heartlands along the coast. A People's Daily article this week noted that 40% of the lakes in Jiangsu – a wealthy workshop province – have dried up in the past 30 years.

Pressure on food supplies is also coming from pollution. More than 12m tonnes of grain have been contaminated with heavy metals, according to a China Economic Weekly story earlier this week. Picking up the thread, South China Morning Post noted a 2007 warning by the former land minister Sun Wensheng that at least 10% of China's 120m hectares of farmland is affected by cadmium and other toxins.

If evidence was needed of the impact of pollution on food supplies, it was provided by another People's Daily report on Tuesday about irrigation from a "black reservoir" in Tanggang, Henan, that withered the nearby wheat crop.

The government has pledged to ramp up efforts to decontaminate the worst areas, to double spending on water conservation and to use weather-modification batteries to squeeze every possible drop out of passing clouds. Rain would have the added benefit of dousing the smog that has built up again in Beijing after an unusually long spell of clear skies.

But it is not just the capital's wheezing populace hoping for a shower. With China's grain hoarders and international commodity speculators alike watching intently, the metereologists of Beijing have more reason than usual to hesitate about making predictions.