What was the reason for conditional waiver given to 8 countries by US?

If the Trump administration takes away the waiver in the foreseeable future, securing insurance for crude and refineries, payments and finding alternative crude sources would be the major concerns for

Indian oil importers received temporary reprieve when eight countries including India got conditional waiver from the US to buy oil from Iran. Shine Jacob explains what the waiver means for India and the problems it might face if Iran imports dry up in future.

What was the reason for the conditional waiver given to eight countries by the US?

The eight countries that got a waiver from the US are India, China, Italy, Greece, Japan, South Korea, Taiwan and Turkey, after they agreed to opt for a “significant reduction” in oil purchases from the Persian Gulf country. The reasons for