Fumigation started last night, with popular route buses like Valletta, Mater Dei, Sliema, Msida and Buġibba among the first to be treated
It doesn't say with what..
Maltese public buses and terminuses will now be regularly and “rigorously” fumigated as new precautions against the spread of COVID-19 are rolled out by Transport Malta and Malta Public Transport.
Images of terminuses in both Malta and Gozo as well as interior and exterior shots of buses being cleaned by professionals fully kitted out in protective gear were released today.
Each fumigation operation lasts about five minutes per bus, and the operations are set to take place in the bus depots of the Marsa Park and Ride, Ċirkewwa and Victoria, Gozo at night.
https://lovinmalta.com/news/maltese-and-gozitan-public-buses-and-terminals-fumigated-rigorously-as-new-covid-19-measures-rolled-out/