The Pasig River, one of the most polluted rivers worldwide

The Pasig River  is a river in the Philippines that connects Laguna de Bay to Manila Bay. It has been considered one the most polluted water course of the world.

Stretching for 25 kilometres, it bisects the Philippine capital of Manila (population: 20 millions) and its surrounding urban area into northern and southern halves. Its major tributaries are the Marikina River and San Javier river.

The total drainage basin of Pasig River, including the basin of Laguna de Bay, covers 4,678 square kilometres.

The Pasig River is technically a tidal estuary, as the flow direction depends upon the water level difference between Manila Bay and Laguna de Bay. During the dry season, the water level in Laguna de Bay is low with the river's flow direction dependent on the tides. During the wet seasib, when the water level of Laguna de Bay is high, the flow is

reversed towards Manila Bay.

The Pasig River served as an important means of transport; it was Manila’s lifeline and center of economic activity. Some of the most prominent kingdoms in early Philippine history,. including the kingdoms of Namayan, Maynila, and Tondo grew up along the banks of the river, drawing their life and source of wealth from it. When the Spanish established Manila as the capital of their colonial properties in the Far East, they built the walled city of Intramuros on the southern bank of Pasig River near its mouth.

In Spanish Manila the Pasig River was also an important transport route and source of water. Due to negligence and industrial development, the river has become very polluted and is considered biologically dead. Hundreds of tons of garbage are thrown into the river every month and in some places the water cannot be seen obscured by the floating debris.

Although a commission was established to oversee rehabilitation plans the river remains extremely contaminated. Recently there was information that some progress has been made and aquatic life might have returned to some stretches of its course (requires confirmation).