Step 1: Introduction to the jute industry.
The jute industry is one of the oldest agro-based industries in India. Jute is popularly known as the 'Golden Fibre' because of its colour, strength and economic importance. It is mainly used for manufacturing gunny bags, ropes, mats, carpets, sacks and packaging materials. Most jute mills in India are concentrated along the banks of the Hooghly River in West Bengal due to several favourable geographical and economic factors.
Step 2: Availability of raw material.
West Bengal is one of the leading producers of raw jute in India. The fertile alluvial soil and humid climate of the Ganga-Brahmaputra Delta provide ideal conditions for jute cultivation. Easy availability of raw jute reduces transportation costs and ensures a continuous supply of raw material to jute mills.
Step 3: Availability of water.
The Hooghly River provides abundant water required for processing raw jute. Water is essential for softening, washing and processing jute fibres. The river also serves as an important transport route, making the movement of raw materials and finished goods easier.
Step 4: Cheap labour and transport facilities.
West Bengal has a large supply of skilled and semi-skilled labour at comparatively lower wages. In addition, the region has a well-developed network of roads, railways, waterways and the Kolkata Port, facilitating both domestic and international trade. These transport facilities reduce production and distribution costs.
Step 5: Market and industrial infrastructure.
The Kolkata metropolitan region has historically been an important commercial and industrial centre. Availability of banking, finance, machinery, power supply and marketing facilities encouraged the growth of jute industries. The proximity to a large market further supports industrial development.
Step 6: Historical development.
During the British period, Kolkata was the capital of British India and emerged as a major trading centre. British entrepreneurs established jute mills along the Hooghly River because of easy access to raw materials, port facilities and export markets. This historical concentration continues even today.
Step 7: Final conclusion.
Therefore, the concentration of jute industries in West Bengal is due to the availability of raw jute, abundant water, cheap labour, efficient transport, port facilities, large markets and historical advantages.
\[
\boxed{\text{Raw Jute + Hooghly River + Labour + Kolkata Port = Jute Industry}}
\]
Most jute industries are located in West Bengal because of the availability of raw jute, abundant water from the Hooghly River, cheap labour, excellent transport facilities, Kolkata Port and historical industrial development.