(a) Two important by products of sugar industry are : 

1. Molasses: It is a kind of dark brown syrup that drains from sugar during the process of manufacture. It is used to produce industrial alcohol, fertilizer, rum etc. 

2. Bagasse: It is the rejected cane left after being crushed. It is mainly Used for manufacturing paper, fibre board etc. 

(b) Punjab is the largest producer of woollen textiles because : 

1. Raw material is easily available as sheep rearing is the main occupation in hilly areas adjoining Punjab. 

2. Demand for product is high because of very cold winters. 

(c) Problems of jute textile industry : 

1. Demand for jute products have decreased due to synthetic substitutes in national and international markets. 

2. India faces a problem of shortage of raw jute as most of the jute growing areas went to Bangladesh after partition. 

3. Obsolete machinery and inefficient or uneconomic units. 

(d) (i) Mumbai is the country’s most important cotton textile manufacturing centre. 

(ii) Two geographical reasons are : 

1. Mumbai’s hinterland, the black regur soil produces the raw cotton required. 

2. The humid climate of Mumbai favours the production of yams of finer counts.