Residents in Port Harcourt, a harbour in Nigeria's oil-producing Niger Delta region, staged protests to complain about heavy air pollution blamed on an Asphalt factory.
The protesters showed their hands covered in soot from touching cars to point out the level of soot posing a threat to their health and contaminating the city.
"The awareness is a very necessary requirement because a lot of us are suffering, from our nostrils, from the water we drink, from the water we bath to everything. You wake up in the morning to black particles surrounding us and making us unhealthy," said Myne Wilfred, a protester.
Authorities later shut down a Chinese asphalt plant after receiving complaints about heavy smog coming from its furnace that is blamed for people suffering from coughing and covering homes with black soot, officials said.
Asphalt products are used in road construction but scientists say particle pollution like soot is a health hazard that can be linked to the risk of heart disease and stroke.
"A Chinese construction company named CGC... has been shut down," the government of Rivers State said in a statement. Port Harcourt is the state capital.
"The asphalt plant was found to be producing thick black smog out of the furnace in the process of burning asphalt, heavily polluting the air," it added. "All the directors of the company will be prosecuted."
"These matters -- we can go and shut down two or three plants, we rebound two or three sites, but this matter eventually strikes at the very fabric of our federal system. We must make sure we control this situation," said Austin Tam-George, Rivers State commissioner for information.
Implementing environmental rules
Charles Adolor and his family say their apartment has soot covering everything from windows to bathroom sinks.
Adolor also says his son has been suffering from a persistent cough which he suspects has a lot to do with the air pollution.
"If you look around my apartment, my window, the veranda, the window nets, my kitchen, the sink, even to the bathroom. If I am having my bath the colour of the water, the stains on the sink is always black. Sometimes it take more than extra effort before you can even wash them off. Before we can use already washed plates, we have to re-wash them again before we can use them to eat," said Adolor.
Environmental rules are often not implemented in the West African nation due to weak state resources and widespread corruption.
In the Niger Delta's oil-producing swamps, residents have complained for years about crude spills from broken pipelines and acid rains from gas flaring - the wasteful burning of natural gas at oil wells.