Now that IS a patch of gas fields - Dolgellae (Dolphin)

I suspect the original image is IR and it's VERY sensitive to gas flares compared to city lights. Note the string of oil and gas fields down the middle of the North Sea, and the huge energy output of kuwait and Iran/Iraq

There are also big energy centres in Western Canada, that are probably gas fields, and the Niger delta is jumping - far more than its population density and civilisation level suggests.

Then there are the West African gas fields off Angola and the Congo, and the northern Pakistan gas fields, and the offshore gas fields of the Australian Nirt-west shelf (better economy here, less gas wasted), and the PNG highlands at Kutubu, and Siberia, and lake Maracaibo in Venezuela, and...

In fact, there are dozens of offshore gas fields visible, that all make sense to me as a petroleum geologist.

I was just surprised to see the Argentinan gas flaring (hugely wasteful, of course)

So this is NOT a map/image of visible light pollution but of thermal IR pollution.