Air travel, public transport and many other services are expected to be disrupted in Belgium on Wednesday.
This happened after major trade unions called for work stoppages over high energy prices and falling purchasing power.
Brussels Airport has cancelled more than 200 flights and is advising passengers to check in early and not bring checked luggage, Belgian news agency Belga reported.
Airline TUI fly has moved several flights to airports outside Belgium including in Cologne and Maastricht and is providing shuttle buses for its travellers.
Domestic trains are either expected not to run at all on Wednesday or to run at reduced capacity in the different Belgian provinces, Belga said.
Public transport is also to be affected throughout the country with Brussels subway operator STIB-MIVB bracing its customers for disruption on social media.
Personnel at private hospitals in Brussels and Wallonia are also expected to participate in the walkouts, Belga reported, with emergency and essential treatments being maintained while many other appointments were being rescheduled.
Several gatherings and marches were planned in different Belgian cities throughout the day, Belga reported.