The most polluted city in the world, according to the WHO data, is Onitsha, a fast-growing port and transit city in south-eastern Nigeria that recorded levels of nearly 600 micrograms per cubic metre of PM10s – around 20 times the WHO recommended level.
In 2013, two people died of heat exhaustion after a six-hour gridlock on the city’s bridge over the river Niger. Cars and trucks on the main road to Lagos belch fumes from burning low-quality diesel, and the air often stinks of burning waste from rubbish dumps, the smoke from old ships on the river and discharges from the metal workshops.
But people did not expect Onitsha in Anambra state on the eastern bank of the mile-wide river Niger, to be named the most polluted in the world.
According to the WHO, an air quality monitor there registered 594 micrograms per cubic metre of microscopic PM10 particles, and 66 of the more deadly PM2.5s. Onitsha’s figures are nearly twice as bad as notoriously polluted cities such as Kabul, Beijing and Tehran and 30 times worse than London.
“We know pollution is very bad here. But this city must be much better than Lagos,” said Solomon Okechukwa, a sceptical Anambra state official, on Wednesday.
But Onitsha, say academics, is a textbook example of the perils of rapid urbanisation without planning or public services creating a sustained pollution assault on its water and air.
As a tropical port city which has doubled in size to over 1 million people in just a few years, it is frequently shrouded in plumes of black diesel smoke from old ships; it has no proper waste incineration plants; its construction sites and workshops emit clouds of dust and its heavy traffic is some of the worst in Nigeria.
A recent study of Onitsha’s water pollution found more than 100 petrol stations in the city, often selling low-quality fuel, dozens of unregulated rubbish dumps, major fuel spills and high levels of arsenic, mercury, lead, copper and iron in its water. The city’s many metal industries, private hospitals and workshops were all said to be heavy polluters emitting chemical, hospital and household waste and sewage. Read more