Rahu Kalam is considered inauspicious to start any new ventures or for any positive activities. Before we start any good deed, we start any auspicious activities only after looking at Rahu kalam, yamakandam, Kulikai, etc, and enter into those activities. Rahu kalam and Yama gandam are both equally considered inauspicious. Kuligai Kal is considered good. According to Astrology, Rahu kalam

Which is 90 minutes in a day is not taken into consideration for performing good deeds. Because that 1 and a half hours will be under the control of Rahu, a malefic planet among nine planets.

Auspicious things, auspicious talks, starting a new business, entering a new house, buying new things, and starting a new job are avoided during this time due to Rahu. From time to time it is believed that everything done or started during the Rahu period ends in hindrance. Not only auspicious activities, when we need to start treatment for the first time medicines should not be started during Rahukalam. Pills prescribed by a physician must also be taken only during the auspicious time, Not during Rahukal.

Although the initiation of spiritually auspicious activities during the Rahu period is avoided, it is said to be the most important time for worship. The Rahu period is the best time to get rid of any problem that a person may have and get the blessings of goddess Durga. It is believed that any problem caused by any planet will be solved if worshipped during the Rahu period. Rahu and Ketu are Serpent planets. So both Rahu kalam and Yamagandam are considered poisonous hours.

Yamagandam:

Yamagandam is also considered inauspicious. Yamagandam also is one and a half hours in a day. This time is influenced by Kethu and auspicious deeds should not be carried out during Yamagandam. On each day in a week, the timings differ and it is calculated according to Sunrise and Sunset.

Unpleasant activities should be avoided during Yamagandam. Any bad deed done during Ketukalam or Yamakandam brings bad results to the doer.

Unpleasant activities should be avoided during Yamagandam. Any bad deed done during Ketukalam or Yamakandam brings bad results to the doer.

Fate affects all living things. Apart from Rahu and Ketu all other planets have taken up a day in a week. But Rahu and Ketu instead of a day, have taken an hour and a half in each day.

People who like to keep their house clean all the time can clean the house during the Rahu, yamakandam period. This is believed to keep the house clean.

People who are unable to sell their land, those who are struggling due to marriage restrictions, and those who are facing the problem of unemployment can worship at Yamakandam.

Monday Rahu kalam:

7.30 to 9.00 am

Monday Yama gandam:

10.30 to 12.00 am

Read more : https://www.astroved.com/astropedia/en/monday-rahukalam-and-yamagandam-timings