With CSS set to text-align:justify; text-justify:auto, when large gaps appear between justified words in Tamil text the browser will automatically expand/contract the inter-character spacing for the affected line.

[r12a]

Test link(s):

text-align:justify; text-justify:auto

Results:

• Gecko: ❌ Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:94.0) Gecko/20100101 Firefox/94.0
• Blink: ❌ _Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_157) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36
• Webkit: ❌ _Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_157) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.1 Safari/605.1.15

Related tests: Text alignment & justification