Increasing term insurance coverage - should I buy additional policy?

I bought a term insurance policy 5 years ago when I was 30 years old with coverage of 25 lakhs. Now I am 40 years old and my income has increased significantly. I also have a home loan of 75 lakhs and my family expenses have gone up. I feel 25 lakhs coverage is not enough anymore. Should I buy an additional term insurance policy or should I increase the coverage in my existing policy? If I buy a new policy, will I have to undergo medical tests again? What will be the premium difference? I am currently with HDFC Life, should I stick with them or explore LIC or Kotak Life?