Some people in Manipur live in houses built on floating islands of weeds and decaying vegetation held together by suspended silt. These islands are called

The floating mats on Loktak Lake in Manipur are locally called Phumdis (also spelled phundis or phoomdis) — heterogeneous masses of vegetation, soil and organic matter that form floating “islands” on the water and support human settlements and huts built atop them. The lake is noted as the largest freshwater lake in northeast India and uniquely characterized by these floating phumdis, which provide habitat and livelihood for local fishermen and communities [1]. Detailed descriptions note that phumdis consist of matted vegetation, sediments and decaying organic matter, held together by roots and trapped silt, and are the distinctive floating islands of Loktak where people live.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > Loktak Lake > p. 30