The race was planned to run for 44 laps, but ended during the third lap due to wet conditions. Laps one and two took place behind the safety car before a red flag stopped the race on lap three. The sporting regulations required the results be taken from the end of lap one, with half points given to drivers who finished in the top 10 positions as less than 75% of the originally scheduled race distance had been completed.

https://en.wikipedia.org/wiki/2021_Belgian_Grand_Prix