There is no doubt; the lockdown has actually helped India contain the spread of the disease, especially when you think of the fact that India is the second-most populous country in the country. However, it will not be a very good judgment if we think the lockdown has been very effective towards containing the spread of the disease in India.
For instance, countries like Spain, Italy, and the USA are also using the same measure, but their current coronavirus cases are way more than that of India. Currently, India has about 90,000 coronavirus cases, unlike the USA, which has recorded over one million cases. So many people believe that India is not testing enough compared to other aforementioned countries.
Another reason could be that the country is underreporting its coronavirus cases. Although, we cannot downplay what the lockdown has achieved towards containing the spread of the disease, however, India hasn't been testing to its full capacity like other countries.