In China, nearly two-thirds of groundwater -- the worst offender -- and one-third of surface water were graded as unfit for direct human contact in 2014, the Chinese Ministry of Environmental Protection said in a report Thursday. What's more, less than 4 percent of the nearly 1,000 surface water sites monitored by the ministry met the highest standard in 2014, Reuters reported.

The environment ministry uses six grades to rate China’s water supplies, with Grade I being the highest. Just 63 percent of the monitored sites were ranked good quality -- Grade III and above -- meaning they are suitable for human use. That figure was down from about 72 percent the previous year.

China’s underground water is getting more polluted, according to the 2014 report. The ministry classified about 62 percent of the 4,896 monitored groundwater sites as either “relatively poor” or “very poor.” This was an increase from 2013 when about 60 percent of samples from 4,778 sites ranked in the same categories.

In April, the Chinese government promised to raise the availability of good, potable water rated as Grade III or above within five years to more than 70 percent in the country's seven major river basins and to more than 93 percent in its urban drinking supplies. The government has said it will also ban water-polluting plants in industries such as oil refining and paper production by the end of 2016.

In an effort to clean up the nation’s heavily polluted waters, the Chinese government has made pollution a criminal act, with violators facing jail time and fines. China’s textile industry has been one of the heaviest polluters in the country, and apparel makers are facing mounting government pressure to cut water pollution and transform factory wastewater into potable water, the Wall Street Journal reported.

But reducing groundwater pollution and increasing the availability of potable water will take time. “[Contamination] of groundwater is complicated,” Wu Shunze, deputy director of the environmental ministry’s Chinese Academy of Environmental Planning, told MarketWatch. “After cutting off pollution, a long process is needed to make repairs, and changes will not be apparent in one or two years.”