Hi dheeraj, blessings. What are you eating in your diet right now? Are you eating refined foods, or junk foods? A diet that is raw will help with this. Mostly fruits and vegetables, stay away from breads, dairy, and sugar for now. You can start to introduce lassi with ginger and cardamom into your diet later. Do three days on raw fruits and vegetables, then introduce the lassi, and slowly introduce natural cooked foods.
There is also a medicine for plugged sinus. It is the oil of mustard, vacha, pippali, vidanga, ginger, black pepper... Put in three drops in each nostril. This is for (Puti Nasya), and is very effective.
For the constipation, take a teaspoon of triphala mixed with 4Xs the amount warm water first thing in the morning, and right before bed. Relieving the constipation will relieve the sinus congestions...
Also are you doing Ujjayi pranayama? I find this one is very effective for clearing the sinuses.