Infrastructure development caused by rapid urbanisation is the main reason for the growth of middle class in Asia.

This statement seems more like a claim or a hypothesis rather than a question. However, I can explain how infrastructure development caused by rapid urbanisation could potentially lead to the growth of the middle class in Asia.

1. Urbanisation: Rapid urbanisation refers to the fast-paced migration of people from rural areas to urban cities. This is often driven by the search for better job opportunities, higher wages, and improved living conditions. In Asia, this has been particularly prevalent in countries like China, India, and Indonesia.

2. Infrastructure Development: With the influx of people into cities, there is a need for increased infrastructure development. This includes construction of housing, roads, schools, hospitals, and other public facilities. It also involves the expansion of services like electricity, water supply, and waste management.

3. Job Creation: Infrastructure development leads to job creation. Jobs are created not only in the construction sector, but also in related industries like manufacturing (for building materials), services (for planning, design, and maintenance), and public administration. These jobs often offer higher wages than traditional rural jobs.

4. Rise of the Middle Class: As people move into these higher-paying jobs, they start to earn more and move up the economic ladder. They transition from low-income to middle-income status, contributing to the growth of the middle class.

5. Consumption and Demand: The growing middle class, with its increased purchasing power, drives demand for a wide range of goods and services. This further stimulates economic growth and creates more jobs, reinforcing the growth of the middle class.

6. Education and Skills: Urbanisation and infrastructure development also improve access to education and skill development opportunities. This enables people to acquire the skills needed for higher-paying jobs, further contributing to the growth of the middle class.

In conclusion, while infrastructure development caused by rapid urbanisation can contribute to the growth of the middle class in Asia, it is likely to be one of many contributing factors. Other factors could include economic policies, technological advancements, and global trade dynamics.