Have a question on throughput limit mentioned on the doc https://cloud.google.com/pubsub/quotas.
For ex: Publisher throughput per region is mentioned as 240,000,000 kB per minute (4 GB/s) in large regions.
Is this aggregated limit across all topics put together in the region or this is for each topic separately in the region or it is for each partition in the region?
Quotas are per project, not per topic. Pub/Sub is designed to scale to 10s of GB/s per topic, but it just requires one to request additional quota for the project in which the topic lives in order to ensure there is capacity available in the desired regions.