I think the reason for the decay gas eth in light of the fact that the volume of exchanges against eth has diminished definitely. Meaning the Ethereum network right now not an excess of occupied that is the reason excavators can without much of a stretch interaction every forthcoming exchange.
There's nothing to do with the exchange volumes but just as said by xalolex, it's about the erc20 tokens demand. Well, we can say that there's something to do with the exchanges because it's being traded there and most people are sending their erc20 tokens into exchanges to trade it.
But in actuality, it's just all about the production of many erc20 tokens and the demand that they're having which is making the network clogged which is turning the fee to be higher than before.