law: Indian Easements Act, 1882
  23. Right to alter mode of enjoyment
  Subject to the provisions of section 22, the dominant owner may,
  
  from time to time, alter the mode and place of enjoying the easement, provided
  
  that he does not thereby impose any additional burden on the servant heritage.
  Exception The dominant owner of a right of way cannot
  
  vary his line of passage at pleasure, even though he does not thereby impose
  
  any additional burden on the servant heritage.
  Illustrations
  (a) A, the owner of a saw-mill, has a right to a flow of water
  
  sufficient to work the mill. He may convert the saw-mill into a corn-meal:
  PROVIDED that it can be worked by the same amount of
  
  water.
  (b) A has a right to discharge on B’s land the rain-water from
  
  the eaves of A's house. This does not entitle A to advance his eaves if, by so
  
  doing, he imposes a greater burden on B’s land.
  (c) A, as the owner of a paper-mill, acquires a right to pollute
  
  a stream by procuring in the refuse-liquor produced by making in the mill paper
  
  from rags. He may pollute the stream by pouring in similar liquor produced by
  
  making in the mill paper by a new process from bamboos:
  PROVIDED that he does not substantially increase the
  
  amount, or injuriously change of the pollution.
  (d) A, a riparian owner, acquires as against the lower riparian
  
  owners, a prescriptive right to pollute a stream by throwing saw dust into it.
  
  This does not entitle A to pollute the stream by discharging into it poisonous
  
  liquor.