This was in support of Freedom Day which was celebrated yesterday.

Emirates tweeted a photo of the Burj Khalifa, the tallest building in the world, yesterday as it was draped in a South African flag with the help of special lighting. Dubai did this as a sign of support and respect for Freedom Day, which was celebrated yesterday in South Africa. Other countries like the USA and Switzerland also displayed South Africa flags in iconic places, like Times Square in New York yesterday as a symbol of unity with our country.

https://www.thesouthafrican.com/lifestyle/south-african-flag-burj-khalifa-dubai-freedom-day-video/