To a large extent a part of the problem is the expatriate and residents' attitude towards littering and illegal dumping.
I believe there is a Qatari law against littering with fines attached, however I do not think the police is enforcing it in Doha.
Not a day goes by where I don't see at least one car window roll down and a bag of fast food trash is dumped on the street or see alleys with bags of trash piled.
If the city really wants to increase revenues, a law should be passed making littering a crime with a 500 QR penalty for each occurence.
Then, instead of setting up traffic traps all over town, the police can just issue littering tickets.
If the problem doesn't stop, at least Doha's finances will be in the positive.

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No one lady is ugly, the drink it's not enough!"