LONDON (Reuters) - Passenger traffic at London's Heathrow airport rose 3.9 percent in March, boosted by strong growth on European and Chinese routes, Heathrow Ltd said on Friday. Of the 5.9 million people who passed through the London hub last month, passenger numbers to China rose 15.1 percent year-on-year with India also delivering good growth, the British airport operator formerly known as BAA said. European traffic rose 7.4 percent, despite the continuing weakness of the European economy, with especially strong growth on routes to Italy, France and Norway. ...