latter flows through Muvattupuzha, Aluva, Kunnathunad and Parur taluks. During the rainy season these rivers are full and heavy floods affect the low-lying areas on the banks, but in the summer season, they generally go dry and narrow. The Periyar is stretched over a length of . Forest and wildlife The flora of this district is tropical. The heavy rainfall combined with moderate temperatures and fertile soil support abundant vegetation. Many of the common plants are found in the coastal area, which forms the lowland region. The midland region is occupied by coconut palms, paddy, tapioca, pepper, pineapple and pulses. The lower slopes of the highland region have teak and rubber. Mangalavanam Bird Sanctuary Mangalavanam Bird Sanctuary is located at the centre of Kochi. It covers , supports many species of mangroves and is a nesting ground for a variety of migratory birds. The Managalavanam is called the "green lung of Kochi", considering its role in controlling the city's air pollution. Thattekad Bird Sanctuary Thattekad Bird Sanctuary lies on the northern bank of the Periyar River and covers about . It was founded by ornithologist Salim Ali. The sanctuary is from Kochi. Birds found here include falcons, jungle fowl, water hens, and hornbills. The flora of this area consists mainly of plantations of teak, rosewood, and mahogany. Further on the road, Pooyamkutty forest of the Anamalais is reached. Climate Economy Ernakulam district is the richest district in Kerala and is the biggest commercial centre in the state of Kerala. It contributes the most to the state exchequer in terms of GSVA and tax revenues. It has the highest literacy rate as well as the highest per capita income in the state, along with having the most number of commercialised banks, startups and large scale industries & MSMEs in the state. Its M.G. Road is home to some of Kerala's most prestigious enterprises. Kochi is also the headquarters of some large companies like Federal Bank, Geojit, V-Guard, and Muthoot. The sea along the entire coast of the district and its backwaters are the habitat of various kinds of fish that supply both marine and inland fisheries. Agriculture The eastern part of Ernakulam is primarily agrarian in nature. Rice is the principal crop cultivated in the wetlands. The district is the largest producer of nutmeg and pineapple in the state: more than 55% of pineapples produced in the state is cultivated in