Pelicans and seagulls have begun flying over the bay again, a sign that its waters have recovered their oxygen content and the marine flora and fauna have been rejuvenated, official media have reported.

Havana Bay, which covers 5.2 square kilometers (2 square miles) and has an average depth of nine meters (about 30 feet), for years was considered to be one of the most contaminated zones in the Caribbean due to industrial and community waste from the Cuban capital being dumped there via several rivers and other channels.

In 1998, authorities launched the GTE-BH cleanup program for the bay and the port that opens onto it that included identifying the sources of waste water and chemicals flowing into it.

The program found that 124 industries were “aggressively” dumping waste into the bay and developed plans to reduce their polluting activities, while 53 industries were designated “highly polluting.”

Among the top polluters was the Ñico Lopez petroleum refinery, with its huge chimney emitting a column of black smoke clearly visible from all over the capital.

The Cuban government is planning to transfer that industry and economic activity to the port of Mariel, located some 50 km (31 mi.) west of Havana where the Special Economic Development Zone is being built.