If you smell gas, turn off the main valve immediately and report the problem in the tenant portal. After that, call Stedin 0800-9009 (available 24 hours a day).
To shut off the gas, you must turn off the main valve. The main valve is a yellow knob, which is always next to the gas meter. The gas meter is usually at the entrance of the building in the meter box. You can see some examples of gas meters and the main valves in the pictures below:
