The oxygen dissociation curve is a sigmoid curve that illustrates...

The oxygen dissociation curve shifts to the right when the affinity of haemoglobin for oxygen decreases, which facilitates the unloading of oxygen to the tissues. This rightward shift is known as the Bohr effect.

Factors that cause a right shift include:
1. High partial pressure of carbon dioxide ($\mathrm{pCO}_2$)
2. High hydrogen ion concentration ($\mathrm{H}^{+}$), which corresponds to low pH
3. High temperature
4. High levels of 2,3-BPG

Therefore, high $\mathrm{pCO}_2$ and high $\mathrm{H}^{+}$ concentration will shift the curve to the right.

Answer: High $\mathrm{pCO}_2$ and high $\mathrm{H}^{+}$ concentration