the canister has up to 3 hoses.
one is a vent.
your photo is a carb. you have a carb>?
1989 Vitara Hardtop & 1991 Vitara Softtop
the car has many vacuum and vent lines.
the vent system is a closed system.
there are only 4 ways to fix it, maybe 4/
1: long hard inspections, of all hoses and for rust on parts that cause leaks. (if you disclose body tag , i can send vacuum map, but you never even said country ,much less a tag.)
2: vacuum leak down tests and tricks to find the leak.
3: pressure testing, same... ways.
4: smoke test machine. (a DIY machine is easy to make and is all over youtube, the ways and means,,,,)
the tank, is not free venting. (smog,etc reasons.)
it sends fumes to the charcoal canister. (see vent pipe)
the medium inside the CAN soaks up these fumes.
then when you start the car , the Induction system sucks the fumes from the canister and then burns them. preventing smog and nasty fumes.
the parts must be good, and fitted right.
on some cars. the CAN has 3 tubes.
1 is intake.
2 is induction ( vacuum)
3: is a vent.
i will now guess at country and at your cars market code. ill guess, drum roll......... code 24 Australia...... over 33 markets..
ill assume its not made by santana (spain)
ill assume its a carb model there are 4 evap systems just for this year and market. 1 is EFI. , 3 are carbs.
in the offical book they show 3 carb canisters, and unlike the EFI version
each has 3 nipples
here is the map. (hose map)
if you need tank map, can do that too. but no country or market code or tag, its just me guessing......