The UK government today green-lighted the nearly 18 billion pound expansion plan of Heathrow airport, the second busiest in the world. It decided to build a third runway, ending 25 years of indecision amid environmental concerns.<br/><br/>British Prime Minister Theresa May approved the decision at a Cabinet meeting. A public consultation will now be held on the impact of a third runway at the west London air traffic hub before the final decision is put to MPs for a vote in the House of Commons next year, with any new runway operational only by around 2025.