What is the reason for the low scoring in the NBA lately?

I can't watch every day lately, so I usually just catch bits of it on weekends or during lunch breaks, but it seems like low-scoring games are happening quite often.
Is it because they are calling illegal screens more strictly and players are using off-arm less to drive to the basket?
Or is the overall pace slowing down, excluding teams like LAL, ATL, and MIA?