What it is
Compressed natural gas — mostly methane — stored at about 200 bar in a reinforced tank. Not the same as LPG, and the two are not interchangeable: different fuel, different pressure, different filling equipment, different tank. A CNG car cannot use an LPG pump and the reverse is equally true.
Why finding it is the hard part
The CNG network is small and shrinking in several countries, which makes every station on the map matter more and every wrong entry cost more. A thin network has no margin: miss one and the next may be a hundred kilometres away, or closed.
What the number above does not say
It counts stations tagged fuel:cng=yes in OpenStreetMap, inside the cities Refuelia counts. Untagged stations are missing from it, so the true figure is higher. And the tag records that somebody once saw a CNG pump there — not that it is working, in stock, or still installed.
So what does this map do differently
Where a driver has checked a station, the pin shows when and says a person reported it. Where nobody has, it says so plainly rather than showing a green dot it cannot stand behind. For a network this sparse, knowing that nobody has checked in six months is genuinely more useful than a confident colour.
Using it on the road
Filter the map to CNG and what remains is what has been recorded. No account needed to look. Confirming a station is one tap, anonymous, and takes about as long as replacing the nozzle — and on a network this thin it is worth more than on any other fuel.