a mask indoors. any percentage above that will have an immediate effect, much more attention to be paid to ventilation, and finally, to new treatment protocols which have to be standardised. as the fourth wave crushes across the continent, countries are struggling to ease pressure on the health services and the streets. anna holligan, bbc news, in the hague. our correspondent anna holligan is in the hague. you are exactly where the protests were last night. obviously very different this morning. tell us more about what it was like last night. actually i was here last night. protesters were pulsing police with fireworks and rocks. all of the streets were locked down. the mayor