Chinese tourism officials said citizens from 45 countries including the United States will now be able to visit China for 72 hours without acquiring a visa. The new policy, which begins Jan. 1, will promote regional tourism and more easily allow short term business and weekend holiday travel, officials said. Air China said the new policy will more easily allow international travelers to visit China on layovers or transfer flights in the country\'s airports. The airline said it would also begin working with Chinese local tourism agencies and guide companies to promote one- to three-day itineraries for international tourists.