Japan has embarked on what may be the last great battle in a so-far successful war against environmental pollution. But despite past successes, many experts say eliminating air and noise pollution from congested roads could prove the most stubborn.
Japan has lost its notorious reputation as one of the world's most polluted countries. Only a decade ago, urban rivers and coastal seas were ''dead,'' poisoned by industrial waste discharges, and a permanent haze of noxious gases hung over wide areas from the belching factory chimneys that were a symbol of national economic success.
Virtually the only reminder of those days is the ongoing court battles by victims of pollution-related diseases.
Through a determined government-industry cleanup effort, few beaches remain on the ''dangerous to swimmers'' list, many rivers are now fit for salmon to return to their spawning grounds, there are more blue skies, and the smog curtain has rolled away to give Tokyoites a far better chance of seeing Mt. Fuji than they have had for two decades.
But, after a three-year nationwide study, the Environment Agency's Central Council for Pollution Control has just issued a report that states: ''Traffic pollution problems of noise, vibration, and exhaust gas . . . have yet to be resolved despite various countermeasures taken.
''The situation remains serious, and it is feared pollution will worsen and the areas affected will widen.''
It pinpointed the underlying cause as the fact that ''economic activity is organized with a very great density. . . . The development of means of transport has been so rapid that traffic facilities and land uses to control traffic pollution have failed to catch up.''
When Japanese cities expanded rapidly after the war, no one anticipated the transformation that would occur. Car ownership has reached virtual saturation point, and many families are following the American trend into a second car. Transportation of goods has largely shifted from the railways to the roads.
As a result, four-lane expressways that looked most impressive when they were built in the 1960s are totally inadequate. Behind the main traffic arteries, most Japanese cities are a maze of narrow, twisting alleyways little changed from the rickshaw era. In a predominantly mountainous country with a large population crammed into a very small area, there simply is not enough land available for a proper network of highways to alleviate congestion.
Engineers have tried to overcome this partly by going to the air. Central Tokyo is now crisscrossed by double- and triple-decked systems of elevated highways. With more and more Tokyo workers spilling out into satellite ''dormitory towns,'' it can take three hours or more to drive into the city center, compared to 40 minutes by train. Apparently many people prefer to sit behind the wheel of a car in a traffic jam rather than be jammed sardine-like into a commuter train.
Extremely tight government standards have cut exhaust gas emissions drastically, but this is partly offset by the growing number of vehicles on the road (40 million at last count). Automakers are being asked to eliminate noxious gas emissions as soon as possible.
The Environment Agency would like to see the government develop an overall policy on land use that would allow the creation of ''anti-pollution routes,'' shut off from residential areas, where all truck traffic should be concentrated. To pay for this, it suggests a ''polluter-pays principle'' perhaps levying a special tax on each vehicle and its operator.
The agency also wants to see public transportation by road and rail drastically improved to make use of private vehicles a much less attractive proposition.
Police too are heavily involved. Systems now being tested combine remote cameras and computers to maintain a smooth flow of city traffic. They control traffic lights, allocate extra lanes in the direction of the heaviest traffic flow, and reroute vehicles around holdups, either by means of electronic signs or by computerized traffic information systems many automakers are installing in their new models.