Increasing numbers of college freshmen back legal abortion and stricter environmental laws, but their views on crime and drug use are becoming more conservative, a survey showed.

The poll released Sunday of more than 200,000 freshmen in 1989 by the American Council on Education also found a growing tendency toward political activism.The number of students saying they had earned varsity letters in sports reached an all-time high, while fewer freshmen reported doing outside reading or visiting art galleries or museums.

One dramatic finding was an increase in support for legal abortion. Support had ranged between 53 percent and 59 percent since 1977, but it jumped from 57 percent in 1988 to 64.7 percent in 1989.

"An abrupt change in student attitudes of this magnitude in just one year is most unusual," said Alexander Astin, a UCLA education professor who directed the 24th annual survey. "It may well reflect the students' growing concern about the current Supreme Court's position."

For the fifth consecutive year, concern about the environment grew, with 86.3 percent saying the federal government is not doing enough to control pollution, compared with 83.9 percent in 1988 and 80.9 percent in 1987.

Support for national health care rose to 75.8 percent from 60.5 percent three years before, while support for laws banning homosexual behavior fell to 45.4 percent in 1989 from 49 percent in 1988.

Student support for raising taxes to reduce the federal deficit rose to 28.8 percent, compared with 22.8 percent in 1985. The percentage favoring increased defense spending fell to 24.5 percent, compared with 38.8 percent in 1982.

But the students took more conservative positions on crime and the use of drugs and alcohol. Only 21.3 percent opposed the death penalty, compared with 23 percent in 1988 and 57.6 percent in 1971.

The percentage of students who wanted marijuana legalized fell to an all-time low of 16.7 percent.