Mexico City ? The country that gave the world chewing gum is getting gummed up: The average square yard of Mexico City sidewalk has 70 blobs of discarded chew.

Now Mexico is responding with innovations ranging from expensive sidewalk steam-cleaners to natural chewing gum that breaks down quickly. It’s even telling its citizens (gulp!) to swallow their gum.

The general in the war on discarded chewing gum is Ricardo Jaral, Mexico City’s director for conservation of public spaces. He bemoans the blackened gobs that mar the newly restored 700-year-old downtown area, whose rough, porous paving stones serve as stubborn gum traps.

Jaral has purchased 10 German-designed machines that treat sidewalks with steam and chemicals, and plans a large-scale cleanup starting Feb. 1. He is also looking to launch a public-awareness campaign.

“When you finish chewing a piece of gum, you either have to put in a piece of paper and deposit it in a trash receptacle, or swallow it,” Jaral said.