ABERDEEN seems certain to lose one of its traditional open air markets, and the Castlegate is the site likely to disappear.

The warning came yesterday from Councillor Yvonne Allan, convener of environmental and consumer protection: ''We are getting to the stage that the city council cannot afford two markets.'' A report on the future of the Castlegate, including its possible re-opening to traffic, will be discussed by councillors and market traders again before the summer holidays. The city's other traditional market is at the Green.