Every day, this city’s sewage—20 untreated tons of it—flows straight into Havana harbor. So does untreated industrial waste from the Nico Lopez oil refinery.

Small wonder Havana harbor is among the most polluted water bodies in the world.

When it comes to Cuba, however, problems like these don’t get much attention in the international press. Far more prominent are the latest twists and turns in U.S.-Cuban relations—for instance, news this month that the United States plans to ease up slightly on its hard-line policy toward the island.

So as Cuba’s international relations story unfolds, serious and mounting environmental pollution here quietly takes its toll, threatening land, water, animals—even public health.

Of most immediate concern is the deterioration of water and sewage-treatment capacity, largely the result of a decade-long economic funk Cuba has been in since the demise of its long-time supporter, the Soviet Union.