The primary cause behind Nigeria experiencing widespread water pollution in the "Niger River Delta" region is the oil spills that occur there frequently.
<u>Explanation:</u>
The Niger River Delta is a huge resource of crude oil that is presently producing around 2 million barrels of oil per day.
The extraction activities in this area are not carried out using the best equipment that offer least spillage. Thus, oil spill incidents are frequently encountered in this region.