New Delhi, April 25 -- It's tempting to believe that the world is on the brink of environmental collapse. We are constantly inundated by dire predictions of climate catastrophe and warnings about the planet's imminent destruction. But this is misleading. Rather than spiralling into panic, we should take a moment to appreciate the remarkable progress we've made in improving the environment-and acknowledge that a key factor is prosperity.

This week marked the 55th anniversary of Earth Day. Back in 1970, when it was first held, the world faced some grim environmental challenges. Rivers were catching fire and cities were choked with smog. Air and water pollution were rampant, especially in the industrialized West.

Today, outdoor air polluti...