What's behind the foul smell in Karachi today?

Karachi residents reported a foul smell on Wednesday morning, some likening it to a "fishy" odor. Experts attribute the stench to decaying microscopic marine algae, known as phytoplankton, a natural occurrence. Muhammad Moazzam Khan, a WWF-P marine resources adviser, explained that the unpleasant smell results from the algae decomposing after the monsoon system ends in late September.

Phytoplankton reside in the upper 100 meters of the sea and are microscopic, making them invisible to the naked eye. This phenomenon, also observed in 2024, typically causes a strong odor in coastal areas, which should dissipate within a few days.

The Pakistan Meteorological Department (PMD) and climate change expert Fatima Yamin suggested that the weather conditions exacerbate the smell. A low-pressure system off India's Jamnagar coast is generating winds around Karachi's coastline, combining with air pollution to create smog. As a result, the smell is circulating throughout the city.

The smog, along with the south-easterly wind direction, is causing the air to worsen, but a sea breeze should improve the situation by evening. Other areas, including Clifton, Defence Housing Authority (DHA), SMCHS, PECHS, Korangi, Orangi, North Nazimabad, Federal B Area (blocks 9 and 10), and Saddar, also experienced the stench.

Although ecologist Rafiullah did not confirm any concrete health risks, prolonged exposure to dusty winds and the smell might impact sinusitis.