28 Apr, 14:55··
NS Warns Travelers of Dirty Trains Due to King's Day

Dutch Railways (NS) is advising travelers to expect dirty trains due to mess left behind by revelers during King’s Day celebrations. The trains were not fully cleaned overnight after a large amount of trash and debris was left by partygoers. This situation is expected to continue for several days.
Summarized from the sources above. Read the originals for the full story.
transporttourismwaste