First of all a very Happy and Prosperous New Year 2008 to all readers. I was out of Raipur for field work, so I couldn’t reply early. For the benefit of readers I am reproducing the extract of said articles in short.
1. Combustion (Also called modhya, asthangatha or vikala), occurs when mars, mercury, Jupiter, Venus and Saturn are in proximity with the sun.
2. Combustion takes place when the planets are in the same Rashi as the sun or in the adjacent Rasis.When combustion occurs in latter position, yoga or dasa effects will not be much affected. This is the view adopted in Ayrdaya Ganita.
3. The following are the degrees on either side of the sun within which the different planets become combust, Moon-120, Mars-170, Mercury-110, Jupiter- 150, Venus- 90 ,and Saturn 170.
4. Moon-Combust moon impairs the health of native, excites the humours in the body, and causes pain in head and weak eyesight too much affliction to the moon in any horoscope, denoted balarishta (Infant morality).
5. Mars-Mars gets combust in the sun when he is within 170 from the sun (In retrogression 8 degree).According to Brihat Jataka when mars conjoin sun in combuston, the native will be fond of sinful deeds. This combination gives rise to heart disease and at the same time gives the native power of resistance and endurance.
6. Mercury- Mercury is a fast planet and does not suffer from combustion. But combust mercury is also evil in giving results. Suppose the lagna is Capricorn (19 deg) and mercury (20 deg) is in 4th house with sun (8deg).Here mercury being lord of 6th is combust and hence malefic. It may cause heart trouble to native and also paralysis, since mercury indicates nerves. Generally combust mercury deprives the native to take full advantage of what other planets give, this may cause impediments in speech, difficulty in learning, losses in speculation and trade. If mercury is in own, friendly or in exaltation, he does good even if he is combust. However a combination of sun and mercury is bad when they are malefic by ownership and have evil association or aspect. In such case the native will be fickle minded, unhealthy, illiterate and poor.
7. Jupiter: - Combust Jupiter indicates ill health, indigestion, intestinal and liver troubles etc.
8. Venus: - Venus is an enemy of sun and usually the association makes Venus weak. The native may be diabetic, impotent, averse to women, or sensual and immoral, unhappy married life.
9. Saturn: - Strong Saturn in combustion may make positively evil. Saturn when evil(weak, afflicted) causes unhappiness in life, set backs in profession misunderstanding with father and superiors,scandals,ill fame etc.Combust Saturn is a potent factor to mar a yoga. Suppose Saturn is in Aries along with sun. Here Saturn is debilitated and sun is exalted. The debilitation in the case of one is removed by exaltation of other not by cancellation, but by setting right the defect. But this is possible only if Saturn does not become combust in the sun.
I am reproducing few rules on combustion which I had noted from *your technical difficulties solved* feature, published in old issues of THE ASTROLOGIAL MAGZINE:-
 
1. When a planet is combust but occupies own or exaltation house, the planet will not continue to be malefic.
2. When a planet is combust but is retrograde- No difference.
3. When a planet is combust but the lord of the sign in which combustion occurs is himself combust, the situation will be worse.
4. When a planet is combust but is aspected by the lord of the sign occupied by it, then there will be 50%improvement
5. When a planet is combust but it is maraka or badhaka for lagna, then the situation will be worse for it.
6. When a planet is combust but is a yogakaraka, then pity will be the greats.
7. Combustion effects will be mitigated by the aspect of a functional benefic or the strength of lord of the combust planet.
8. A planet though posited in debilitation, inimical house, or is combust, when occupies an auspicious house or amsa, would yield mixed results in Dasa and pretty good ones in latter of Dasa. (Phaladeepika)
9. If sun is debilitated and if any planet is combust with it (Libra or adjacent sign), then combustion effect will not operate due to Sun’s debilitation.

Thank you for your enlightening views on combustion.

After reading the excerpt, I have a semi-general and semi-personal query for the learned astrologers if you could kindly spare some time. In my chart, Mars in combust but placed in own sign and in a different house than Sun. It is forming Ruchak Yoga. However, uptil now I really don't see any major positive effect in my life. In fact my professional life is quite messed up despite excessive / more than required effort. (DoB-18 May 1981; Time: 11:05 am; Place: Patna, Bihar)

Hence, I am forced to question both theories in my case (combust plant in own sign removes evil effect; combust planet placed in another sign than sun minimizes effect of combustion)

I have posed this question in other forums also. One of the astrologers told me that the Ruchak Yoga comes into force only in the 28th year of the native that is why results are delayed for me.

Please let me know your views on this. Is there something malfic which I am overlooking in my chart. I am wearing a 3 ratti red coral in silver.

Shrikanthji,
  Thank you very much for giving us the information.
Very useful info and some of the things match to what I have seen in my chart and some other relatives' charts.

Ofcourse, there are some questions but I am sure will be difficult to answer without looking at some charts.

Happy New Year to you too.

Shubh,
  Some piece of info - In astrology, timing is everything. There is a particular time when each event occurs - triggered usually by dasa or maturity of the planet signifying an event.

Thanks Rajitha....I'm assuming you are talking about the transits and graha bala. In the chart in question (DoB-18 May 1981; Time: 11:05 am; Place: Patna, Bihar), Mars' graha bala is "vriddh" or old.

Does the graha bala affect the combution of a planet in any way? eg. Combustion situation is worsened if the planet is "vriddh"/ old or "Mrit"/ dead.