Israel is under siege again.

The air is filled with fumes so noxious that people might be tempted to reach for their gas masks.Highways are choked with cars, so many that the country seems to have come to a standstill.

And garbage is piled so high that it poses a hazard to jets streaming in and out of the international airport.

The enemy is pollution, the kind every industrial society generates. Only here it's especially troubling, because the tiny state is growing faster than most developed countries as it continues to welcome Jews from around the world. And because Israelis, preoccupied with their physical security, are only beginning to acknowledge that environmental evisceration also threatens their survival even as they celebrate their nation's 50th birthday.

Israel's 268 people per square kilometer make it more thickly settled than India (261), and fast approaching Japan (327). It gen-er-ates 50 percent more solid waste per person than England, and it devotes two-thirds of its precious supplies of fresh water to serve farmers at subsidized prices.

And while most developed nations have managed to put the brakes on their population explosions, Israel continues to grow 3 percent a year. The reasons are understandable - from continued immigration of Russian Jews to a biblical imperative among the Orthodox to have large families. The results, however, are equally predictable: The nation's population is expected to double by 2020, which means that 50,000 new housing units will be needed each year simply to keep pace.

"Since Israel wants to grow and wants all the people, then we'll have to plan it a little better," conceded Miriam Haran, a top scientist at the Ministry of the En-vi-ron-ment and ex-wife of Prime Min-is-ter Benjamin Netanyahu. "We hope we'll be able to set targets and do it more carefully than it has been done to now."

Philip Warburg, an environmental attorney and activist in Jerusalem who moved to Israel after years working on U.S. environmental issues, was less sanguine: "One of the depressing things about the current situation is that, in times of political stress, the environment falls to the bottom of the heap. And we're entering a period of political stress that I think will set the environmental movement back to where it was before the peace process began.

"The United States may have been able to afford 20 to 30 years to develop a mature environmental consciousness, but Israel cannot afford that luxury."