China has tightened controls on internet use, requiring anyone who wants to set up a website to meet regulators and produce ID documents. <br/><br/>The Technology Ministry said the measures were designed to tackle online pornography, but internet activists see it as increased government censorship. <br/><br/>A number of websites are now being registered overseas in an attempt to avoid controls. China has the world's biggest online population: more than 380 million users.<br/>