Türkiye's main opposition-run Istanbul Metropolitan Municipality (IBB) came under renewed criticism Tuesday after officials from the ruling Justice and Development Party (AK Party) said a dive in the Golden Horn revealed severe pollution, accusing the city administration of failing to preserve one of Istanbul's most iconic waterways.

The event, organized by the AK Party's Istanbul Environment and Urban Policies Directorate to mark World Nature Conservation Day, aimed to highlight pollution in the historic estuary.

Zakire Nurdoğan Yüzbaşıoğlu, AK Party's Istanbul deputy provincial chair and head of its environment and urban policies unit, said visibility underwater was limited to about 30 centimeters, making it difficult for divers to navigate.

"I couldn't even see the other divers," Yüzbaşıoğlu remarked. "We encountered thick layers of mud on the seabed and had to hold hands for safety. The sludge was extremely dense and dark. It is impossible for marine life to survive under these conditions."

She underlined that the Golden Horn requires another comprehensive dredging and environmental rehabilitation program to restore its ecosystem, urging authorities to increase water circulation in the inlet and remove accumulated sediment.

Recalling restoration projects carried out during President Recep Tayyip Erdoğan's tenure as Istanbul mayor in the 1990s, she noted the Golden Horn had once regained a cleaner environment but claimed unpleasant odors had returned, particularly during humid and rainy weather.

Moreover, AK Party Istanbul Metropolitan Municipality council member Özlem Erol also criticized Republican People’s Party (CHP)'s municipal cleaning operations during the event. She said several boats operated by ISTAÇ, the municipality's waste management company, approached the diving area but did not conduct cleanup work.

Erol alleged the boats remained near the group without carrying out cleaning activities and said the municipality should maintain regular environmental operations in the Golden Horn.