Information regarding driving bans for Diesel-powered vehicles and particular environmental zones as well as information on how to apply for an exemption can be found via the following links:
https://stadt.muenchen.de/infos/umweltzone-muenchen.html
https://www.muenchen.de/verkehr/autos/umweltzone-und-diesel-fahrverbot-muenchen-alle-infos
https://stadt.muenchen.de/service/info/gewerblicher-kraftverkehr/10223253/