This might not be the main reason for your website positions going down, but it's something that will keep you from going up. Most of your visitors are from India, if you test a website speed for mobile users (with fast 3G connection) from India you'll see that it's rather slow https://webpagetest.org/result/191225_WA_972a2ca7545ba636e9a31c2dc3f0f7f3/ Site speed continuousely stated by Google as an important ranking factor that you definitely would take into consideration. You should aim to make your SpeedIndex at least twice better to rank high in Google (now it's 2.9s for the homepage). More information can be found here https://sabrinazeidan.com/tag/site-speed/