A memorable scene in the movie Slumdog Millionaire, set in Mumbai, depicts the boy hero plunging into a ghastly pool of liquid excrement. Truth isn’t much stranger than fiction. The city of 18.4 million people is running out of space for its waste, and Deonar, Asia’s oldest and largest dumpsite, is bursting. Each day, more than 500 trucks line up along a two-lane dirt road in an eastern suburb, waiting to add to a mountain of refuse tall enough to submerge the White House twice over. That pile began in 1927 — the year Charles Lindbergh completed the first trans-Atlantic solo flight.