Bhubaneswar is topographically divided into western uplands and eastern lowlands, with hillocks in the western and northern parts. Kanjia lake on the northern outskirts, affords rich biodiversity and is a wetland of national importance. Bhubaneswar's soils are 65 per cent laterite, 25 per cent alluvial and 10 per cent sandstone. The Bureau of Indian Standards places the city inside seismic zone III on a scale ranging from in order of increasing susceptibility to earthquakes. The United Nations Development Programme reports that there is "very high damage risk" from winds and cyclones. The 1999 Odisha cyclone caused major damage to buildings, the city's infrastructure and cost many human lives. Floods and waterlogging in the low-lying areas have become common due to unplanned growth.