As per the Liberalized Remittance Scheme (LRS) of the Reserve Bank of India, a person can consume foreign exchange only upto 2.5 lakh US dollars or its equivalent to other currency cumulatively in a financial year. So you can calculate the limit upto which you can carry SGD for your Singapore dollar trip depending on your earlier consumption of foreign exchange in the current financial year.
However, one thing you should keep in mind is that as per the RBI norms, you can only carry upto US $ 3000 or equivalent in cash while travelling abroad. If you wish to carry more Singapore dollars, you need to carry it digitally like by loading SGD on your forex card.