Which party headed the National Front that formed the coalition government in 1989 ?

Janata Dal

The National Front (which itself was an alliance of Janata Dal and some other regional parties) received support from two diametrically opposite political groups: the BJP and the Left Front. On this basis, the National Front formed a coalition government, but the BJP and the Left Front did not join in this government. Thus, the National Front government was the coalition to keep the Congress out of power. It was led by Janata Dal.
The United Front was similar to the National Front of 1989 for it included Janata Dal and several regional parties. This time the BJP did not support the government. The United Front government was supported by the Congress.