It is in the eastern coastal plains, along the axis of the Eastern Ghats mountains. The city has an average altitude of above sea level. It lies southwest of the Mahanadi River that forms the northern boundary of Bhubaneswar metropolitan area, within its delta. The city is bounded by the Daya River to the south and the Kuakhai River to the east; the Chandaka Wildlife Sanctuary and Nandankanan Zoo lie in the western and northern parts of Bhubaneswar, respectively. 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. Urban structure The Bhubaneswar urban development area consists of the Bhubaneswar Municipal Corporation area, 173 revenue villages and two other municipalities spread over . The area under the jurisdiction of the Bhubaneswar Municipal Corporation covers . The city is somewhat dumbbell-shaped with most of the growth taking place to the north, northeast and southwest. The north–south axis of the city is widest, at roughly . Growth in the east is restricted due to the presence of Kuakhai River and by the wildlife sanctuary in the northwestern part. The city can be broadly divided into the old town, planned city (or state capital), added areas and outer peripheral areas. It is subdivided into Units and Colonies. The old town or "Temple Town", the oldest part of the city, is characterised by many temples, including the Lingaraja, Nilakantha Siva, Rajarani and Muktesvara temples, standing alongside residential areas. Additional structures include the Somabaresvara Siva Temple and the Kartikesvara Siva Temple. The area is congested, with narrow roads and poor infrastructure. Among neighbourhoods in the old town are Rajarani Colony, Pandaba Nagar, Brahmeswara Bagh, Lingaraja Nagar, Gouri Nagar, Bhimatangi and Kapileswara. The planned city was designed in 1948 to house the capital. It