Answer: 2. As many landfills run out of space, some communities are making plans and tackling their heaping piles of garbage with innovative solutions.
The main idea in this passage is that landfills in America are running out of space. Because of this, some communities are finding innovative ways to deal with their garbage. The rest of the passage provides details about these innovative ways. Some of the things that the passage mentions are recycling and turning trash into energy.