The oil is pollution and seeps into the soil, possibly the groundwater. 

Or, is someone just tired of the signs, which are illegal in some communities, may be illegal without first paying for a permit, or simply considered a nuisance by someone living or working in the area and you are polluting their neighborhood in their mind?

Pollution dropped, outside litter reduces, plastic bag reduction etc.

On the other hand, we have awful traffic, crime, and pollution, and there are panhandlers on nearly every corner.

According to its site: The Host Protection Insurance program does not apply to liability arising from (1) Intentional Acts including: (i) Assault and Battery or (ii) Sexual Abuse or Molestation - (by the host or any other insured party), (2) Loss of Earnings, (3) Personal and Advertising Injury, (4) Fungi or Bacteria, (5) Chinese Drywall, (6) Communicable Diseases (7) Acts of Terrorism, (8) Product Liability, (9) Pollution and (10) Asbestos, Lead or Silica. 

Philly was the land of unequal opportunity where certain blocks have more pollution, crime, problems.

Administer a methane polluter fee to reduce carbon emissions.$37 BillionCommittee on Homeland Security and Governmental AffairsElectrify the federal vehicle fleet (including USPS and Non-USPS).