Begusarai is known as the Industrial capital of Bihar. There is an industrial complex at Barauni in Begusarai which is situated on the bank of river Ganga. Barauni industrial town has the potential to become the industrial capital of Bihar. The major industries are Indian Oil Refinery, Barauni Thermal Power Corporation, Hindustan Fertilizer Corporation, Barauni dairy, Bihar Carbon Pvt. Ltd., Neo Carbon Pvt. Ltd., Premier Industries, Graphite India, etc. There are also several small industries in the private sector.

The district known as the Industrial capital of Bihar is Begusarai. Begusarai is located in the eastern part of Bihar and is known for its industrial development and economic growth. Here are the reasons why Begusarai holds this title:

1. Industrial Infrastructure:
- Begusarai has a well-developed industrial infrastructure with various industrial areas and parks. The Barauni Industrial Area and the Begusarai Industrial Area are the major industrial zones in the district.
- These industrial areas house a wide range of industries including oil refineries, chemical plants, fertilizer factories, thermal power stations, and textile mills.
- The presence of these industries has led to the establishment of ancillary units and small-scale industries, further contributing to the industrial growth of the district.

2. Barauni Refinery:
- One of the key factors that contribute to Begusarai's industrial prominence is the presence of the Barauni Refinery.
- The Barauni Refinery, operated by Indian Oil Corporation Limited, is one of the oldest and largest oil refineries in India.
- It plays a significant role in meeting the petroleum product requirements of Bihar and the eastern region of the country.
- The refinery also provides employment opportunities and boosts the local economy.

3. Employment Opportunities:
- The industrial development in Begusarai has led to the creation of numerous employment opportunities.
- The presence of industries such as oil refineries, chemical plants, and textile mills has attracted a large workforce to the district.
- Many people from neighboring districts and states migrate to Begusarai in search of employment in these industries.
- The availability of jobs has contributed to the economic growth and prosperity of the district.

4. Economic Contribution:
- Begusarai's industrial sector makes a significant contribution to the economy of Bihar.
- The industries in the district generate revenue through production, manufacturing, and export activities.
- The economic growth resulting from the industrial sector has a multiplier effect, leading to the development of other sectors such as transportation, trade, and services.

In conclusion, Begusarai is known as the Industrial capital of Bihar due to its well-developed industrial infrastructure, the presence of the Barauni Refinery, abundant employment opportunities, and its significant economic contribution to the state.