Some advertising networks are reducing their ecpm very rapidly

It appears that online advertising rates are decreasing very rapidly in the last few months.
Some of the advertising networks are reducing their advertising rates very rapidly
One ad network was offering $0.025 CPM till April
They reduced the ecpm to $0.015 in May
Now they have further reduced the ecpm to $0.007 again in May
In contrast the ecpm for video ads which are autoplayed remains the same at $0.2