Silk, known as pattu, has a long history in India and is generally produced today. Historically silk was used by the upper classes, while cotton was used by the poorer classes. Today silk is mostly produced in Kanchipuram, Dharmavaram, Mysore, etc. in South India and Banaras in the North. "Murshidabad silk", well-known from historical times, is mostly produced in Malda and Murshidabad district of West Bengal and woven with hand looms in Birbhum and Murshidabad district. The silk from Kanchi is mainly well-known for its classic designs and enduring quality. The silk is traditionally hand-woven and hand-dyed and regularly also has silver threads woven into the cloth. Most of this silk is used to make saris. The saris usually are very expensive and vibrant in color. Garments made from silk form an integral part of Indian weddings and other celebrations. In the northeastern state of Assam, three different types of silk are produced, together called Assam silk: Muga, Eri and Pat silk. Muga, the golden silk, and Eri are produced by silkworms that are native only to Assam. The heritage of silk rearing and weaving is very old and continues today particularly with the production of Muga and Pat riha and mekhela sador, the three-piece silk saris woven with traditional motifs.