Evergreen International Airlines has asked the Civil Aeronautics Board for permission to delay for six months the announced November start of its nonstop scheduled air service fro the Washington area to the Yucatan Peninsula in Mexico.

Evergreen, awarded the exclusive route earlier this year, had planned to begin nonstop service to the Yucatan from Baltimore/-Washington International Airport on Nov. 23 and already had taken a number of reservations.

Earl Tawney, Evergreen's vice president for scheduled services, said the airline was helping passengers who had booked on Evergreen get seats on other airlines, albeit not nonstop service, but was not able to guarantee travelers would get tickets at the same price.

Evergreen's fares had not been approved by the CAB yet, he said. About 250 individuals had booked with Evergreen, and more seats had been made available in blocks to tour wholesalers, he indicated.

Evergreen officials cited a light response to marketing efforts and an insufficient number of hotel rooms at the Mexican vacation spot as the major reasons for requesting the delay.

The airline, which carried cargo and passengers only on charters until airline deregulation presented it with new scheduled service opportunities, also told the board it could not start its recently awarded routes to the Yucatan from New York and Cleveland.

Because no other airline had applied for authority to fly from Washington to the Yucatan, Evergreen may be granted its delay and Washington will be without nonstop scheduled service there, at least for the present.

In the case of its service from New York, however, Evergreen is likely to lose the route to United Airlines, which had wanted the route and was given backup authority by the CAB should the first-named airline renege.

Evergreen told the board it would start the service from New York next year if United didn't want if after all, but a United official said it would take the route.

The CAB has been sensitive on the question of delays requested by newly designated airlines for exclusive routes. Earlier this week, it denied Braniff Airways' request to delay inauguration of its newly awarded Yucatan route from Dallas/Fort Worth until next summer, saying that if Braniff fails to begin its service by Nov. 10, it proposes to award the route to American Airlines.

Altogether, 11 new routes from U.S. cities to the Yucatan were made this year under terms of the U.S.-Mexico air services bilateral agreement, which limits major routes to a single U.S. airline.

Evergreen continues to operate scheduled service from BWI to Freeport in the Bahamas.