The Industrial Employment Standing Orders Act/Rules are applicable if you are employing/had employed 100 workmen (In some States it applies to 50 workmen, Check for your State)
Under this Act ,Model Standing Orders are given which continue to apply till you get your own certified.
It is unusual that registering authority is asking for standing orders. You may tell them you are following the Model Standing Orders if the Act is applicable and if not no standing orders.
9th April 2019 From India, Mumbai