Maritime traffic has increased four-fold over the past 20 years, causing more water, air, and noise pollution in Maritime shipping traffic has increased rapidly. the world’s oceans and seas, according to a new study quantifying global shipping traffic. Traffic went up in every ocean during the 20 years of the study, except off the coast of Somalia, where piracy has almost completely halted commercial shipping since 2006. In the Indian Ocean, where the world’s busiest shipping lanes are located, ship traffic grew by more than 300 percent over the 20-year period, according to the report published in the journal Geophysical Research Letters. Burgeoning ship traffic has increased the amount air pollution, particularly above the Sri Lanka-Sumatra-China shipping lane, where researchers recorded a 50-percent increase in nitrogen dioxide, a common air pollutant, over the 20-year period. Shipping is also a major source of noise pollution, which can be harmful to marine mammals, the authors note.