DCEite, either the adhesive has gone bad, or the rubber has corroded (typical Maruti cost-cutting). Choose windscreen experts without a second thought. Ask them to send their mobile van to your place and get the work done.
Installing a windshield is no rocket science. Also the so called "glue" is actually a silicone based gel like substance which cures/hardens in approx 2 hours. It is applied using a applicator squeeze gun.
Only precaution to be taken is that the silicone is evenly applied and that there is no gap else you will have water leakage. There are diff makes of silicon and cost ranges from Rs350 a tube to over Rs.1500 depending on the brand.