The trade war between the United States and China and a broader decline in world economic growth are weakening the demand for oil and pushing prices down, the International Energy Agency said yesterday. The Paris-based agency, which advises many developed countries on energy policies, cut its forecast for oil demand growth this year and next as trade tensions weigh on activity in the energy-hungry manufacturing sectors around the world. The U.S. has put a series of tariffs on Chinese trade goods and China has responded by letting its currency drop, increasing uncertainty for businesses and exporters around the world.