How can I purchase shares of listed company where stock is not available in the market

I was looking to buy few stocks listed in BSE, example “AMINES & PLASTICIZERS LTD” ( I see that the stock is locked in upper circuit at Rs 30.15 . I see that there are no shares available in the market to buy but still the price has gone up. How does this happen?

This happens when there is excess demand for the stock. Excess demand leads to buyers buying the stock at any given price exhausting all the sell quantity, hence it hits the upper limit. If you intend to buy the shares then you will have to try buying it the next trading session.