The massive march was sparked by outrage over the government's slow response to the island nation's worst environmental disaster in years.
Thousands of civilian volunteers have worked for days to try to minimize damage to protected marine wetlands polluted by the spilled fuel.
Locals are donning hazmat suits and trying to clean up the oil spill after the MV Wakashio struck a coral reef and ran aground.
An estimated 1 ton of oil has already escaped into the Indian Ocean after a Japanese ship ran aground off the island's southeast coast.
Thousands of tons of diesel leaked into waterways in a major accident at a power plant in Siberia.
Nearly a million gallons of oil spilled at an Equinor storage terminal during the Category 5 hurricane. The cleanup is ongoing.
Environmentalists blast Trump for "contempt" for law and the planet.
More than 660 tons of oil remains aboard the Hong Kong-flagged ship, which is continuing to leak.
Sen. Hannah-Beth Jackson commended the 50th anniversary of the Santa Barbara oil spill by introducing legislation aimed at preventing another such disaster.
An estimated 150 million gallons of oil is believed to have leaked from Taylor Energy's damaged Gulf Coast platform.