The United Nations has given China a $25 million grant to help save the ozone layer by phasing out products that destroy the thin shield protecting Earth from harmful ultraviolet radiation, state media said on Monday.The largest single contribution China has received from a special UN ozone fund would be used to set up factories expected to produce an annual 10,000 tonnes of hydrofluorocarbons (HFC), a less ozone-damaging substance, the China Daily said.