The Mediterranean Sea serves as a vast ashtray for many beachgoers, according to a report on marine litter released by a United Nations environmental watchdog last week.

The report singled out Israel for special praise, due to the Environmental Protection Ministry's "clean beach" program, now in its third year.

The world's seas and oceans will continue to fill up with junk unless urgent action is taken, the UN Environment Program said in "Marine Litter: A Global Challenge."

The study indicated that cigarette butts are the most common debris found floating off of the world's beaches, and that butts, cigarette packs and cigar wrappers account for 40 percent of the waste in the Mediterranean.

Waterborne waste increases 75 percent in the summer months, as tourists join the locals on Mediterranean beaches. Much of the waste appearing in Israeli waters has has traveling south from Lebanon.

Israel's "clean beach" program gauges a beach's cleanliness by the amount of plastic containers within a predetermined area (plastic containers are the second-most common waste product, after smoking products).

Last year, however, only one-third of beaches were labeled "clean."

The UN report said, "There is an increasingly urgent need to approach the issue of marine litter through better enforcement of laws and regulations, expanded outreach and educational campaigns, and the employment of strong economic instruments and incentives."

"Although a number of countries have taken steps at the national level to deal with marine litter, the overall situation is not improving," it said.

Aside from harming tourism and causing "aesthetic" damage, marine litter also takes a significant economic toll on communities, and causes extensive ecological damage.