Dear Sir,
In times of global disputes/unrest, people prefer to buy gold to ensure global security because gold is an internationally accepted currency. Hence in such times, prices of gold rise high, and the share market shows a downfall.
Coming to your question about the Limit of Gold purchases, please note that “Income tax act’ does not prohibit a person from buying gold. Further income tax does not set any maximum limit for buying physical or digital gold but there are some rules which should be followed. Please refer following points about gold purchases:–

1. Gold & Silver are subject to GST @ 3% (HSN 7106, 7108, 7109, 7111). Please ensure to obtain a proper GST invoice. GST is applicable on both physical as well as digital gold.  
2. Furnishing PAN card, is made mandatory for purchasing gold above Rs. 2 lakh. 
3. TCS u/s 206C(1h) @ 0.1% is to be collected on sale on gold above Rs. 50 lakh. If TCS is collected then the buyer need not to deduct TDS u/s 194Q @ 0.1% otherwise TDS provisions are applicable. 
4. Ensure that Gold purchase in properly reported and IF GOLD holding of a person is not justified by his income then he may have to face penal provision under IT ACT. 
5. Sovereign Gold Bonds(SGBs) are government securities denominated in grams of gold. They are substitutes for holding physical gold. SGB can be held in Demat form. The face price of SGB is fixed in proportionate to the gold price of 999 purity. Investors will also get interest @ 2.5% p.a. and SGB prices will also increase with an upward change in GOLD prices. Hence investors of SBG will get a return more than physical gold. Further, he will save on part of GST (as no GST on SBG) and marking charges (as no making charges in SBG like gold ornaments). But there is a lock-in period in SGB for 5 years. After which investor can sell SGB but capital gain on SGB will be taxable. But if he holds SGBs for 8 years then capital gain on SGB is exempt. Hence for long-term investment in gold, SGBs are better than physical Gold. 
6. GOLD ETF is only for short-term investors as there is no lock-in period in GOLD ETF. Investors can buy or sell as their own choice. But there is no fixed interest paid in ETF which is paid in SGB (2.5% p.a) The only gain in GOLD ETF is the rise in the price of gold. Hence long-term investors choose SGB over ETF. 
7. GOLD Mutual Funds, is a tool for small investors to take advantage of the rising prices of GOLD through combined funds. GOLD mutual fund further invests 99% of the accumulated fund to GOLD EFT and other short-duration government securities. Hence the return of GOLD Mutual Fund is not far away from GOLD ETF. 

The above points may be helpful for making your decision to investment in GOLD.
 
Thank you.