Here is an article explaining the effect of the liquidity in the underlying stocks of an ETF on the ability of the market maker to keep the Bid/Ask in line with the value of the underlying basket of assets.
With respect to your question, there are two factors that I can highlight -
- The underlying equity basket in this case is top 50 stocks on the NSE which are likely to be always high in terms of liquidity.
- Whether you believe in the ability of the ETF sponsor/ Authorized Participant to perform their activity effectively.
Disclaimer - The article explains about ETF activity in US, there might be differences in how ETF’s operate in India. If so somebody else can expand on that.
This is a diagram on the NSE website explaining the structure of an ETF https://www1.nseindia.com/products/content/equities/etfs/structure_etf.htm