"Keep in mind the next time you are in China and find yourself choking on the foul air that the things making the air foul are counted as positives for GDP. If you adjust Chinese GDP for environmental degradation and for over-investment in things that will never be used, it falls in size by 30-50 per cent. Much of this would show up as non-performing loans in most economies but since such loans are never recognised in China, it will show up as slower growth in future years," he said.