Reuters: The ports of Los Angeles and Long Beach, comprising the busiest U.S. cargo complex, launched a landmark clean-air program on Wednesday banning some 2,000 older trucks blamed for half the pollution spewed by the ports’ diesel haulers. The port complex ranks as the biggest air pollution source in Southern California. Heavy-duty trucks contribute well over a third of the ports’ overall diesel exhaust emissions and are the most visible to local residents, the ports have said. The …