Why do so many shops look so dirty in London and its suburbs ?

London is and pretty much always has been something of a toilet!

That's just how the city is. Other than a few central touristy bits it's very much a working city and looking great is less important than getting on with stuff. If you want gleaming streets go to Paris.

The city is actually home to some of the most impoverished UK communities and the contrast between rich and poor boroughs can be quite shocking. Run down shopping centres are not confined to London in the UK either. The economic stagnation of the last decade coupled with changing consumer practices like online buying have seen many high streets across the UK brought to points of crisis. Streets which were once bustling with stores have been reduced to betting shops, vaping shops, pound stores and pawnbrokers. The variety of yesteryear seems sadly lost.

London is a dirty city.

I don't know what sort of shops you are talking about. Many small businesses in the shopping world are finding it very difficult to make a profit due to the power of the supermarkets, ridiculously high rents and business rates

because council don't clean them

A majority of London are minorities now.

Deandre has been in them.