As the search is on to find a solution to the problem of illegal constructions in Delhi, it has come to light that as many as 70 per cent of the Capital's buildings are unauthorised. The statistics were made available by planning experts at a meeting of a high-level panel set up by Congress to search for a way out of the situation arising out of the ongoing High Court-ordered demolition drive against unauthorised constructions, sources said. The meeting was also told that while on an average 70 per cent of the buildings were unauthorised in MCD areas, 50 per cent of buildings in DDA-approved areas were illegal. The figure stood at 20 per cent in the areas under NDMC.