The general observation is that the applications workload is balanced between Ottawa and LVOs of native country. It is random, but probability of Ottawa office is high for parents visiting Canada.
For your PCC from India, you may contact BLS to process it for you. It may take 4 to 6 weeks though for them to process it. Alternatively, you may check with state government if someone in India can submit PCC application on behalf of your parents. For Punjab, it is possible to have representative. For Chandigarh, it may not be possible. Every state is going by their own rule. The PCC can take longer if the parents stayed at more than one place for 6 months.