RT PCR REPORT - Indirect flight

[a_sharath]

Hi,
Travelling from Chennai to Toronto:

1. Is negative RT-PCR reports required only from India or even from transit countries?

2. If I travel from Chennai to Toronto , via Dubai or Paris or Frankfurt.
a. will there be any transit visa required in other countries?
b. do we need to take separate negative RT-PCR test in transit countries as it is not direct flight?
c. is Canada allowing people travelling through indirect flights and carrying negative RT-PCR report only from India ?

Please help.