Learn how to say Unsustainably correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word unsustainable:
1not able to be maintained at the current rate or level:
macroeconomic instability led to an unsustainable boom
Ecology upsetting the ecological balance by depleting natural resources:
unsustainable fishing practices
2not able to be upheld or defended:
both remarks are unsustainable