New Delhi, 19 December (NNS): The prices of big cardamom Kainchicut improved by Rs 20 to Rs 1690 per kg owing to improved sale even after the increment in the prices. Recently, the prices have improved by Rs 10 per kg. The average auction price reported to be at Rs 1475/1800 per kg in the last auction which held during the previous day. There is no fear of downfall in the prices during the coming days.