Chinese regulators have approved Google\'s $12.5bn (£7.9bn) purchase of US phone maker Motorola Mobility, the final hurdle for the deal to go through. Chinese authorities said Google must keep its mobile software, Android, free for other device makers for up to five years. The acquisition, would be Google\'s biggest ever. It has already won clearance from US and European regulators. Google\'s purchase of Motorola Mobility allows it to move into manufacturing of phones and tablet computers for the first time. It also gives Google access to more than 17,000 of the company\'s valuable patents, which will help it defend itself and Android phone manufacturers in patent disputes. Google said the Chinese government cleared the deal on Saturday.