Weight guidelines have been issued for school bags depending on a child's age after studies showed heavy loads can affect soft, developing spines.

Teachers have also been told to not give children in grades one and two homework so they do not need to carry heavy books home.

A survey by the Associated Chambers of Commerce and Industry of India found 68% of pre-teen children might suffer from mild back pain which can develop into chronic pain and later into a hunchback.

More than 2,500 children and 1,000 parents in major cities were surveyed, with more than 88% of children from seven to 13-years-old carrying more than 45% of their body weight on their backs.

Mother-of-two Rashmi Tapke, said heavy schoolbags are a reflection of poor time-table planning by schools.

"If they [schools] plan, they can repeat the subjects taught and thus reduce the load. My kids find it difficult to carry so many books," she said.

In Maharashtra state, where Mumbai is, full schoolbags should not exceed 10% of the child's body weight.

Many schools there are now using white boards and projectors so children do not have to carry text books.

Some cross rivers with books on their heads to get to school.

"My frail daughter has to haul about 4-5kgs of books in her school bag and also carry her lunch box and water bottle in a separate bag," said driver Rajinder Shukla, whose child goes to school in Uttar Pradesh state.